Sony Field Monitor CLM-V55 (HDMI-input), a not bad monitor, but is not ideal, merely a 5.6-inch screen, and lacks the tablet feature.
http://i411.photobucket.com/albums/pp196/benesotor/11x0113uob34.jpg
http://i411.photobucket.com/albums/pp196/benesotor/11x0113ub45sony.jpg

Field Monitor (With HDMI port) in B&H,
A lot of knockoff field monitor, and all of these lack the tablet features.
http://www.bhphotovideo.com/c/search?atclk=Monitor+Inputs_HDMI&ci=1984&N=4028759510+3887600136

Field Monitor (With HDMI port), by Amazon US himself doing sales, (not from third party).
A lot of knockoff field monitor, really shoddy, and all of these lack the tablet features, merely a shoddy monitor. 
http://www.amazon.com/s/ref=sr_nr_p_6_0?fst=as%3Aoff&rh=n%3A172282%2Cn%3A502394%2Ck%3Afield+monitor+HDMI%2Cp_6%3AATVPDKIKX0DER&keywords=field+monitor+HDMI&ie=UTF8&qid=1426413828&rnid=303116011

Note, nobody who are willing to whilst carry around the two devices -- a tablet and another field monitor, especially a long journey over hill and dale.
So, to do it 2-in-1 to be the one best way, (2-in-1: the HDMI-input feature added to a tablet).

Kodrut, Please read more:

About the HDMI-out playable on a tablet ‎(Posted at 07-30-2014 10:22 AM)
http://forums.toshiba.com/t5/Encore-Tablets/For-the-next-WT8-A-What-are-you-wishing-for/m-p/601214#M7889

For the next WT8-A, What are you wishing for?  (Posted at 07-30-2014 10:01 AM) 
http://forums.toshiba.com/t5/Encore-Tablets/For-the-next-WT8-A-What-are-you-wishing-for/m-p/601198#M7888

----- "some apps on the tablet that can interact with the camera or accessories like a remote, right?"

Oh, no. Kodrut, you need more to understand about the camera.
At a high-class camera, the Live-View mode and HD-video are directly capable of outputting from the HDMI-out port of camera, rather than the viewing in field is just in a merely 3-inch screen of the camera body.

Also, the camera will automatically play back the just taken each photo by every time shutter, which the high-class camera is also whilst outputting into the HDMI-out port, so you can use an outer monitor of 8.5-inch screen and is also automatic playback each photo from the camera, no longer must operate an OS at the viewing. Makes you can more focus on camera operation, but a larger outer monitor is whilst available.

Taking HD-video can be directly outputting from the HDMI-out port of camera, rather than just doing of record at the flash card.

you can access the following websites, please note, it is still very trouble and limited to single brand camera, while capability is also unideal. Also, in Windows 8.1 has no similar apps.
http://www.davidkennardphotography.com/blog/805-using-the-nexus-7-android-tablet-as-a-dslr-controller-and-monitor.xhtml
http://studium.tobiasdeml.com/2012/11/11/monitoring-a-canon-dslr-on-set-with-an-android-tablet-hd-on-camera-with-peaking-for-215-dslr-controller-in-a-real-life-film-product-environment/

If a tablet comes with an HDMI-input feature, will resolve all of matters.
Also, nobody who are willing to whilst carry around the two devices -- a tablet and another field monitor, especially a long journey over hill and dale.
So, to do it 2-in-1 to be the one best way, (2-in-1: the HDMI-input feature added to a tablet).

----- "my professional photographers friends have A LOT of cards to carry around, then they process the stuff at home on their computers."
Please talk a field monitor and viewing photos, as well as meanwhile a journey, and not saying the home to do post-process, thanks.

Always is merely to use A LOT of cards?
If that is just a newsman shooter and is fully nothing to the art photography, which case is possibly the only exception.

P.S.
If Intel is still not clear about all above, continues turning a deaf ear, which is a really extreme bad thing.

When I take pictures I usually have enough space on my card. Obviously I'm not shooting any RAW images. In your case, I guess you also have some apps on the tablet that can interact with the camera or accessories like a remote, right? As I said earlier, my professional photographers friends have A LOT of cards to carry around, then they process the stuff at home on their computers. Or laptops, one of them moved from desktop to a MacBook Pro and says he's never going back. ;)

Why a tablet and the HDMI kit carry with, instead of a lightweight laptop?

I. At the shooting field as my need to be a tablet (the best is an 8.5-inch screen), rather than a lightweight laptop comes with fixed mode keyboard.

II. A touchscreen is needed, or even with a stylus included, rather than must operate a keyboard.

I believe you must not be a photography lover, did not have relevant experience.
Unspeakable, when you are controlling a camera on the tripod, but whilst must operate a keyboard.
Also, an opened laptop would turn into a much larger shape, and also considerable trouble to hold on hand as the use.

I bet Apple will now sell some USB splitters/hubs for ridiculous prices soon. ;)
P.S. Just wondering... why carry around a tablet with that HDMI kit instead of a light laptop/convertible for more serious endeavors?

HDMI-out,
For a usual 8.5-inch tablet is that I mainly use the 8.5-inch screen at outdoors, but indoor or a hotel room the tablet will be used as my main computer tool when, well then I would more be willing to connect it to a larger display device (monitor or HDTV), not just a small screen.

I have a set of HDMI kit, also able to connect to DVI or VGA, not just the HDMI of display is available, like this
My HDMI Travel Kit (for a Toshiba WT8-A 8-inch tablet), posted at 09-26-2014 06:50 AM:
http://forums.toshiba.com/t5/Encore-Tablets/%C2%B5HDMI-to-VGA-converter-that-works-with-Encore-8/m-p/616201#M8354

a "one size fits all" connector,
Never want to get an only USB port to be acted as a video port part-time, unless it comes with the two USB ports at least, but is still with another HDMI-out port would be better.   

did you know about the newest Macbook has attracted Apple fans' anger?  ----- "And like the iPad, it only has one port, which is the cause of the outcry."
http://techcrunch.com/2015/03/10/apples-latest-betrayal/

e-Compass,
When you came into a cavern or tunnel, GPS becomes unavailable, have to use the e-Compass.
Besides that, the e-Compass is also more uses, for example, when came into a strange place you can be beforehand to know about local Sunrise position via using the e-Compass, very useful to a shooter.

I understand USB and GPS, maybe e-Compass as well, but why HDMI? The awesome part about Type-C USB is that you can drop a bunch of different cables and ports and only have one connector for multiple uses. Slowly we're getting close to a "one size fits all" connector. Hopefully same will happen with all these cables as well...

USB, HDMI, GPS and e-Compass are necessary on a tablet, very useful. (Not be willing of a buy, when a tablet lacked those features)

Undoubted, USB 3.1 and with a Type C port must be better.

When a tablet adds with HDMI-input feature will undoubtedly gain in wide purposes and markets, if in the future someone did.

GPS/GNSS must be compatible to the mode NMEA 0183 + virtual COM, (Windows 8/8.1 the sensor API and Location API the way is damnable)

The USB 3.1 has much more uses, say like HDMI-input while in tablet can borrow a USB 3.1 port to connect accessing an outer device HDMI-out,  through using an HDMI-out/USB converter.

People have ever asked for Intel adds the HDMI-input capability at the tablet and laptop, makes it can be switched to act as a field monitor capable of being outdoor use, no longer just to run an OS, but is no any response from Intel.

All of these high-class cameras have an HDMI-out port.
Sony PalyStation has HDMI-out, a lot of  media players have HDMI-out.
Also, an HDMI-input feature also builds up the tablet's added-value, like for IT maintenance aid tool, or is a sub-monitor comes with HDMI-input, etc, etc...

of course, a tablet certainly needed an HDMI-out port,
But, HDMI-input and HDMI-out able to use a physically single micro-HDMI port, because you are impossible at the same time could need the HDMI-input and HDMI-out, based on a tablet.
I select a tablet (or laptop) that is certainly having an HDMI-out port,  despite the tablet is an 8-inch screen (16:10), or is 8.5-inch better, (16:10).

And, therein said above is merely one of many examples.
However, just in the interchangeable lens cameras are the shipping qty over 10 Million units each year since after 2006. The recent years, these shipments are almost close to 20 Million units each year. Besides the interchangeable lens cameras, in addition there is a lot of  high-class fixed lens cameras as the shipping qty in each year.

There are not just being professional photographers, the amateur and camera lover are far a much huger market to these tablet makers. But so far, therein lack satisfactory products (from an affordable price), especially for Windows tablet.
(do not welcome these knockoffed-Windows-tablet, very dislike Atom z3735G/F, extremely junk chips)

"Not that they're the only ones to do so... look at AMD and NVIDIA"
Okay, so have to say, AMD was already not as good as Intel, Nvidia was already not as good as Intel. But, Intel was already being behind competitors in the mobile market, is that Intel wanted to become second AMD?

MS + Intel = the two losers in tablet market,
Intel has to admit himself extremely dereliction.

Oh yeah, I know. I got a few buddies who are professional photographers and they usually carry a lot of class 10 cards with them. Moving RAW files around while in the field can be quite a time killer. I think Intel is still pulling some juice from old technology. Not that they're the only ones to do so... look at AMD and NVIDIA, for example.

Although USB 3.0 is much faster than  USB 2.0, but is not an excuse becomes Intel to continue using their old designed USB 3.0 I/O that 2 years ago.

Surely, very wanted the USB 3.1 and Type C port,
The examples one, in the fields and outdoors, when taken the RAW format photos and then the files bulk to transfer into tablet via the USB connection.
I think that you already knew about the RAW format photos, what is size of files.

Even, many who taken the HD video later to import into the tablet, could they care nothing about USB 3.1? do you really think so?
(Note, not to say phonecam or webcam, for the photos and video)

Also, Intel wanted their designed USB I/O to be behind competitors, steps like the mobile chip, again?

Do you really believe USB 3.0 is that slow? It's not like there's that much of a difference between 3.0 and 3.1 as between 2.0 and 3.0, after all.