A while ago I dug up some info on devolution, the Wii GC backup loader alternative to DIOS MIOS, that suggested that Tueidj hated GC pads and had some different input methods ready for action.
Today I spotted over in GBAtemp forums a small but significant snippet of information regarding use of PS3 controllers on Wii and WiiU:
there is a way to get a PS3 controller to work with wii homebrew, the controller will only work on the wii with a usb charging cable connected, no bluetooth connectivity. The author of devolution, or somebody else, would have to implement this into devo. It does work, I tried a version of the snes emulator that had this installed to it, worked on the Wii and Wii U.
We knew based on Tueidj’s DevolUtion youtube vid that he had PS3 pads working, and today we know precisely how!
SickSaxis is a C library that lets you connect a Sixaxis or a DualShock3 to the Wii and read its data. It also lets you turn on and off the controller LEDs, enable or disable the rumble and get and set the controllers’ bluetooth MAC address.
This means (providing the authors recompile their apps with this lib included) we should no longer need a classic controller or GC controller for homebrew and emulators, and blows wide open the possibility to properly map GC controls to a PS3 pad on vWii when DevolUtion drops!
Source: GBAtemp forums