There's a project floating around that reverse engineers the game pad protocol to allow building a custom replacement with a Linux machine and an Android tablet

There's a project floating around that reverse engineers the game pad protocol to allow building a custom replacement with a Linux machine and an Android tablet, but it's a bit involved. The way the WiiU tablet works requires hacking up the Linux wireless stack, IIRC. Cemu and Dolphin are great, if you feel like homebrewing the console and dumping all your games to play on PC.