Apparently, Nvidia had to iron out a few problems with the Turing chip production, so the mobility versions needed to be delayed for a few months. The RTX 2000 mobility lineup is now expected to debut at CES 2019, with general availability slated for early February. Inside sources claim there will be 2080, 2070, 2060, 250 Ti and 2050 models, plus Max-Q versions for the top two.
https://www.notebookcheck.net/Nvidia-set-to-reveal-the-RTX-2000-mobility-lineup-at-CES-2019.374321.0.html