Last year we reported that Hyperkin took its GameCube-inspired 'ProCube' controller to EVO to get feedback from the competitive Smash Bros. community. It's wireless and compatible on Wii U as a Pro Controller (so no Wii Remote is needed), and takes the inputs and control style of the GameCube and makes them accessible in a whole lot of games; as it stands actual GameCube controllers only work with compatible adapters on Wii U, and then are only recognised by Super Smash Bros. for Wii U.
For fans it's obviously tempting, and the reception to the pad was obviously strong enough to persuade the company to move into full manufacturing. It's now opened pre-orders on the controllers, with black, white and purple models available for $29.99 (though shipping may be added depending on where you are). You can see it from a few angles (and colours) below.
Though heavily inspired by the GameCube pad, its digital shoulder buttons bring it into line with the standard Wii U Pro Controller.
If you're interested in pre-ordering one you should head for the official website; they're expected to ship on 1st February.