The Raphnet Wii Classic Controller to USB is the real del. It's seriously as good as a Wired Xbox 360 guitar. Legitimately buy one of these if you have a Wii Guitar.
raphnet] N64 controller to Wiimote adapter | eBay
raphnet. - Neo Geo controller to USB adapter
raphnet. - Classic controller to USB adapter - V3
raphnet. - Classic controller to USB adapter - V3
raphnet. - Genesis/SMS/Atari controller to USB adapter
raphnet. - Sega Saturn controller to USB adapter (v2)
Raphnet Classic Controller to USB Adapter V3 Wii Guitar Drum Turntable New Japan | eBay
raphnet. - Classic controller to USB adapter - V2
raphnet. - N64/Gamecube to USB adapter - V3
raphnet. - Dual Gamecube controller to USB adapter
raphnet. - Dual NES controller to USB adapter - V2