Hey Ben,
Me and my group of friends have been thinking about building a Game boy Color (With Back-light) into a calculator, however we don't want to invest anything into the project until we have seen it done by a professional. Basically, the project uses a large scientific calculator as the case and a game boy. In theory it should be fairly simple, just tear down a Game boy and a calculator add a few switches. The only hitch is that we want it to be as concealed as possible with a headphone jack and volume controls. Also we want it to still loo like a calculator (With a few extra switches and a different screen). If you would consider this as a build idea we would be very happy and would try some engineering feats of our own. Thanks, Lucas