I wasn't sure if I wanted to put this under this section, or gaming, but while killing time on the internet last night I stumbled across a linux distro called "Lakka". It appears to be an OS straight up just for game emulators, with a PS3'ish interface. It's using the Libreto api.
Anyone tried it? It looks pretty sweet, but I guess it's in early'ish development.
You could install the emulators on the Wii U. It's a little bit of work but nothing too complicated. There are emulators for pretty much any older console (except Sony consoles). I have used SNES, N64 and Genesis/MegaDrive emulators on my Wii and not to forget there is backwards compatibility with GameCube games. In this case it's nice to have a Wii classic controller to play the older games though it's not really necessary.
But compare to Retropi its nothing that new. Just a stolen PS3 interface in my opinion. but best to create a new post in retorgaming for this stuff if we want to continue.