ive been successful in flashing a modified rom (just updated es file explorer, taskmanager and maps, removed quickoffice, that handwriting app, and a few of the live wallpapers i never use) ...
i originally tryed flashing my 4gb image to a friends 2gb pad (after dumping his original backup.img and system.img)..but it just crashed on boot just after the little android icon appears..so i flashed his original rom back and all was fine...
next i used newtuxflash to edit his dumped system.img (not the one thats in update.img..its locked!).. i removed the apps and then flashed it back.. (both methods work, from file on sdcard called update.img or from USB & RKAndroidBatchUpgrade.exe pointing to the .img on your system).. some of the apps didnt show up...i checked the system.img i editied with newtuxflash and found the apks had spaces in the names, once i removed the spaces, signed the system.img and reflashed, they all showed up perfectly, even entirly new ones (battery meter on the notification bar)
next i will workout how to add su/root
for anyone looking for a rom...the best way is to make your own i think..RKCooking.. linked a few posts above.. has everything you need to dump, modify, sign, and flash YOUR own ROM (everything except a temp root tool and root file explorer to workaround a few issues mentioned above) theres too many different versions of the pad out there (yet they all have the same model number!)