In the beginning of 2003, the 9th of January, a patent was filed in the U.S. for a very GameCube-like controller with a screen. The patent is written under the name of Mark Siegel, although from what I can remember, when I first saw the image, it had some sort of connection to Nintendo - but I may be wrong. I sure hope not, so this patent doesn't somehow conflict with the release of this very cool console.
I've already contacted Nintendo for a comment... will see if I get a reply, although maybe a quicker, better reply would be more likely if N-Europe contacted them?
Here's the image associated with the patent:
home.no/yagami/20030220142.jpg