Did we get it working on Wii yet?
No.
Note: This topic is present in 4 forums to raise awareness, and to make sure that anybody who can contribute information knows how.
Since there's a lot of interest in getting this backwards-compatible through hacking, I figured I'd make a thread detailing what's known about it so far.
For those who don't have one, it's basically a Classic Controller Pro without the wire and with the player LEDs from the Wiimote slapped on the bottom.
The idea is that through modding the System Menu, we can use the WUPC as if it were a normal Wiimote with a Classic Controller Pro attached to it.
The controller does connect via Bluetooth, and so the original Wii system already has the necessary hardware. We don't know the PIN yet.
I'm not sure if it can pair via the USB charging cable, but if it does we can simply use that to pair.
If you have any useful information that you think should be in this post, reply and I'll be sure to put it in.
TL;DR if you have new info post it!
Resources:
WiiUBrew info on WUPC: http://wiiubrew.org/wiki/Wii_U_Pro_Controller
Use WUPC with your PC: http://gbatemp.net/threads/wii-u-pro-controller-to-pc-program-release.343159/