"NintendoGal.com Interviews Amber McCollom E3 2011

AM: My name is Amber McCollom and Iím the Director of Entertainment & Trend Marketing at Nintendo of America.

[...]

NG: I noticed on backwards compatibility at the press conference that the GameCube was missing. Why is this?

AM: You know itís interesting that you bring up backwards compatibility and Nintendoís history usually goes back one system. The Wii was compatible with GameCube and Wii U will be compatible with Wii and thatís pretty traditional in launches from Nintendo.

NG: So the Wii U will not support the discs or accessories?

AM: Actually the GameCube discs will not be compatible with Wii U, but a number of the games that were playable on GameCube can be downloaded from WiiWare."
Source- nintendogal

I really hope this is real... I loved Mario Sunshine and Mario Strikers on GC