Chris Manning has transformed Nintendo’s Wii U GamePad into a PC friendly device. The video below shows how you can re-map the GamePad to almost anything needed for a game’s input.. If you can configure the code you could use it for most contemporary titles as well, even the Dolphin emulator.
Here is his video of the Wii U GamePad in action (playing Zelda)..
In his description he states “Follow the readme.txt closely! This requires a bit of technical know-how to get working. For more assistance with using XAMPP (my preferred local web server), visit this video” XAMPP is a flavor of Apache, a common web server. Chris also says that the first pending update will add touch-screen support to Wii U’s GamePad. He is also working on getting the games to stream to the GamePad so you can actually play a PC game on a GamePad controller.