Last night I tried flashing 7/20 and 7/29, both will not boot up. 7/29 boot-loop into recovery.
I tried extracting the boot.img from 7/17 (which I have right now working great) and flashing on top, but the tablet will not boot, I just get a black screen after the moto logo goes away, and it stays like that for a long time (until I gave up).
I ended up restoring a nandroid of 7/17.
The tablet is running @ 1.6GHz solidly now, which have never happened before. With some builds, couldn't even run it @ 1.4GHz.
Awesome job all around, thanks everyone for making this happen for the XOOM!