Thanks to TimoBeil in Comments for pointing it out.
Waaaay back in March, a post on the 5Fans forum said Android 5.0.2 was in progress for the iFive Air [Google Translate]. Since then, nothing more has been posted about it either in the forum or on Weibo.
Today, TimoBeil posted a link to an OMA/CrewRKTablets build of AOSP 5.1.1 for the iFive Air and iFive Mini 4: RK3288: Lollipop has landed on rk32board
I note with some frustration the AnTuTu score has dropped from the 40,000-range to the 35,000-range:
This is frustrating for these reasons:
1) Was the original 40,000-range score a cheat?
2) Does this ROM actually drop the score?
3) Do later versions of AnTuTu account for the score drop?
4) A 35,000-range score really isn’t a big advantage over an Intel Atom-based tablet.
Only three tablet brands that I know of use the Rockchip 3288 CPU: Five Technology, Pipo, and Hisense (these tablets are sometimes rebranded outside of China). Perhaps Rockchip has decided with so few partners, it’s just not worth their time to go ahead with an official Android 5.x update? If so, that would make people avoid Rockchip-based products in the future.
Finally, it doesn’t look there’s any MultiWindows 2.0 in this unofficial ROM.