update: I've found the root password -- using the password cracking method and file from geekmaster here:
http://www.mobileread.mobi/forums/sh...d.php?t=160490 (thank you!)
So I'm IN now. I'll try my best to follow NiLuJe's advice above (serial jb + hotfix + mrpi, and then just run MRPI in a shell instead of via KUAL to install the hack). Wish me luck!