I already emailed Minis Forum on a 7945HX model that would be preferred in their standard UM format. Cooling will probably be the issue but I will buy one if they make them.
I'm not sure how much market the external GPU mini-PC has. Though the UM790 Pro and the successor of the HX99G will probably be Minisforum's greatest hits if they can build enough of them.
At its Computex 2023 booth, Minisforum is displaying motherboards that will be featured in high-end mini PCs launching towards the end of 2023. Both the Intel and the AMD models feature a PCIe 4.0 slot for a full-size GPU that can be connected via a riser cable.