This is cool. It's not just for the Atari 2600 anymore! :-)
http://segadirect.jp/Catalog/CustomPages/CustomDetail2.aspx?File=megadra_goods.htm (Though personally, I prefer the bulky consoles; that's why I still have all of mine. ^_^ )
And...wow, Altered Beast. Wasn't that the very first Genesis game? I should go break that out and play it for a bit!