Something of interest, some Sandisk SD cards (the ones that look like this: http://www.fox326.com/bookpic/SDC/SD1GB.jpg) are actually roughly the same size as MMCMobile cards. I don't know if they're all like that, but if the 4GB ones are it's possible that the 770 will accept them as-is.

Here's the dissection guide:
http://jakekerber.vox.com/library/po...issection.html