A time old battle, RK have never released the source code for any of the products, even back in the MP4 player days.
D2K i don't blame you for your weariness from China tabs, at the low pricing for the nexus and kindle tabs i too would recommend to get one of those over the china tabs if you have access to them. Between the flaky firmware and dodgy screens i am now seeing, i really do not see the China tabs getting any better, i kind of see them cutting corners even more now that there are big brands selling tablets for a lower price.
That's too bad. For a long time, I've had an interest in Chinese devices from Ainol, Onda, Teclast, etc. I really preferred the MP4 players a few years ago, while frustrated w/ the lack of music features like sorting. The build it, sell it, and forget it mentality is what drew me to English language forums to weed through all the crappy devices to find a good one that had the features I wanted. Moving to Android hasn't improved their attitude in supporting their tablets. Right now I see the biggest problem is the Android implementation. I am so grateful to the guys and gals at Slatedroid for working on custom roms.
However, I can testify to the value of buying one of the big three value mainstream tabs (Nexus 7, Kindle Fire HD, and soon to be released Nook HD). At $200, it really challenges the market for Chinese tabs. TBH the main reason I bought my Coretab was because it was on sale for closer to $100.