Portable Nintendo GameCube? 
There are two great, but clearly fake, pics of a Portable Nintendo GameCube over at Engaget. And while, someone clearly spent a lot of time making it look slick, it's most definitely an old-school walkman that has been photoshopped into a game system. However, that is not what is important. What is important is the vision. This product would sell like piping-hot-cakes. So any Nintendo execs out there take a note from the comment board and get on it.