Android 5.0 source code was pushed to AOSP less than a week ago, but oma7144, a member of
Arctablet CrewRKTablets, already managed to have a preliminary firmware boot on Odys Iron, a tablet powered by Rockchip RK3188. This is still work in progress, and the firmware image has not been made available for download, but it looks promising, and that means Android Lollipop firmware images for Rockchip tablets and mini PCs could be released sooner than I initially expected.
Some screenshots taken from the tablet.
You can find more screenshots on Arctablet.