I've seen something made by sega that was a little 4" cube that had video outs, power input, and a controller coming out of it. When you power it up you get to choose from six games like: altered beast, kid chameleon, sonic, flicky and two others i think.
It reminded me a lot of those controllers they sell now that have mortal kombat, madden, or nhl games on them and it's a stand alone purchase.
That's the only thing i can think of that comes to mind when i read the descrtiption. however i don't know a name or anythign about a similiar nintendo product.
-jack
http://www.bredberg.org/nes/bestGame.php