Don't just cut a hole out of the top, use plexiglass as a clear window to show the cartridge. That way dust and other crap won't accumulate in there. It should turn out pretty cool.
the color scheme of the NES looks like K.I.T.T.'s Rival K.A.R.R. from Knight Rider. You should try to incoperate a yellow "cylon" light on the deck somewhere ..just a thought
Tattoos, the only thing I collect that I dont have to pack up when I move.