The new 7" tablet/ereader Kobo Vox inside. It is relatively easy to
disassemble (all held by snaps, no glue), but you have to be very careful.
As you can see, the internal ROM is on a removable micro-SD card - so
presumably you can swap it with another one, with an alternative OS image
(CyanogenMod etc). Also, you can see a small button "rst1", which is
presumably a full factory reset button. I haven't tried it yet.
UPDATE: The RST1 button simply reboots the unit. Someone heard from Kobo
developers that there is no special button or combination of buttons which
would reset the unit to the original state. But one can always make a clone
of the internal micro-SD card, to another 8GB micro-SD card. You don't even
have to disassemble Kobo to do that: if you are a bit familiar with Linux,
simply install a busybox and shell apk's on Kobo, insert a new 8GB card in
the external card slot, run the shell, and execute the command "dd
if=/dev/block/mmcblk0 of=/dev/block/mmcblk1". (You might need root access for
that; if so, run first the Gingerbreak v1.20 apk.) Only if you totally
bricked the device, you'd have to disassemble it, and swap the internal SD
card with the copy.
There is a good discussion forum on Kobo Vox hacking here:
www.mobileread.com/forums/forumdisplay.php?f=246