I don't know if any of you are familiar with the homebrew program Devolution, but it is a GameCube USB loader that runs in Wii mode. Since it runs in Wii mode, that means that it has access to all the Wii hardware. It has memory card emulation, you can currently play the Phantasy Star games online, and the creator of the program (tueidj) has plans for adding online support for all games. Anyway, a version of Devolution has just been released that allows you to play GameCube games with Classic Controllers, Wii U Pro Controllers, and PlayStation 3 controllers. This means that it is now possible to play GameCube games on the Wii U. You can read about it here (http://gbatemp.net/threads/devolution-public-release.330554/). Also, here is a video showing a GameCube game running on the Wii U (although there wasn't controller support at this time)...
http://www.youtube.com/watch?v=rlcVdL8r9lk (http://www.youtube.com/watch?v=rlcVdL8r9lk)
Yea been messing with this since yesterday, been playing Wind Waker with my Ps3 controller on the WiiU >:D