The SupaBoy plays plain ol’ SNES cartridges (though only North American cartridges). Battery life is said to be around 5.5 hours per charge. That powers a 3.5-inch LCD.
There is a video output so you can connect it to your TV, and two real controller ports built-in. Though the thought of playing SNES games on an HDTV makes me shudder.
No price listed as yet, but a similar product, the FC Mobile that plays NES cartridges, currently goes for $60. So there’s that.
UPDATE: Video hands-on from E3 2011!