13AM Games looked into GameCube controller support for Runbow
Runbow is going to end up supporting a whole bunch of controllers. You’ll be able to use the GamePad, Wii U Pro Controller, Wii Classic Controller, Wiimote, and nunchuck.
13AM Games producer Dave Proctor told Shacknews that the team also looked into GameCube controller support as well. Sadly, it’s unlikely to be supported because it’s being branded as a Smash Bros. peripheral.
Proctor said:
We have looked into it. It is currently only branded as a “Smash Bros. periperal,” so unfortunately, we can’t get access to that. We do have support for Wii U Pro Controllers, we are working on a patch to plug in seven Wii Remotes, we have support for the Wii Classic Controller, as you’ve seen, and we’ve also added support for the Nunchuk. Worst case scenario, someone’s got a Nunchuk, they can use half the controller. It’s got all the buttons you need. We just want everybody to get the biggest experience they can.