We extend our congratulations to [airz] over at the ben heck forums. He put together a mod that fits an emulator into an original NES cartridge and utilizes a butchered original NES controller; and he did an amazing job!
He is using a cheap but full featured emulator board. It comes with 4 gigs of memory but also has an SD card slot. NES, Game Boy, and Game Boy color ROMs can all be played on the 2.8″ color LCD but the system also features a TV out connector for use with a larger screen as well.
The cuts that [airz] made in the case are amazing, easily eclipsing the last cartridge emulator mod we saw. The holes for the controls look as if the plastic was molded that way. For realism he also cut off the PCB interface on the business end of the cartridge and glued it in place. Apparently it took three cartridges, two controllers, and two of the emulators to make it this nice, but if you want to make an omelet…