I gave Ubuntu on BayTrail a try again and finally did it: the following screenshots are from a Lenovo ThinkPad Tablet 8 BayTrail tablet, running kernel 4.0, Ubuntu 15.10 “Wily Werewolf” and Unity8. I’ll document the necessary steps over the next couple of days.

This is the 7” tablet connected to a 100” projector screen via HDMI. lightdm starts and the display is mirrored to the external screen, but most controls are out of place and the sizes are wrong.