Crack that sucker open and send us some pictures of what's inside, you'll need an o'scope to figure out where the various signal lines are and you'd need some decent micro controller knowledge, but I don't see why you couldn't do it. Just a quick guess from the picture it looks like a standard text LCD module which if you're lucky should have a standard hitachi interface. If it does you're almost ready to go, the keyboard should be trivial to interface with.