We might be getting that demo pretty early in January...
http://www.nintendoworldreport.com/news/55905/monster-hunter-presentation-to-air-thursday
Capcom is airing a worldwide Monster Hunter presentation this week.
The presentation will run on Thursday at 6 a.m. Pacific time/9 a.m. Eastern/1400 UTC and will be focused on March 26's Monster Hunter Rise. It will air on Capcom's Youtube and Twitch accounts.
It is expected - though not confirmed officially - that the demo for Rise announced last month would be made available shortly after the presentation or at least a date provided.