Nintendo just released the trailer for their E3 Smash Bros Invitational, happening June 10th in the Nokia theater and streamed on Twitch. They have a snazzy announcement for the finalists who will be competing and the rules of the tournament, but there's a pretty neat reveal at the end too.
It looks like they'll be providing a special USB-to-GameCube controller adapter, allowing contestants to use the classic control pad preferred by the vast majority of professional Smash players. It's anyone's guess if this thing will go on sale after the tourney but I hope to god it does.
To be honest it's in line with Nintendo's recent trend of releasing stop-gap peripherals (like the 3DS's unsightly Circle Pad Pro) but it's better than nothing. I wish they'd just make a Classic Controller Pro that looks like a GameCube pad, but it is what it is. Who knows if this is related to, or in competition with, the announced (but not revealed) officially licensed Cube-style pads that PDP is working on.
If Nintendo does decide to sell this adapter, I hope they start mass-producing that slick Smash-branded GameCube controller and, god willing, Wavebirds. Those things are getting insane on Ebay.