There are a few concepts out there that fit that bill, and I actually quite like them. I've always been a fan of the Gamecube controller, and I think with a few tweaks it could be great.
Something like this, with a screen the size of the iPhone 6S Plus would be nice. I'd change the face buttons and add those scroll wheel LR buttons. Love the shape, though.
I've always liked the Gamecube controller, and I like this concept a lot, however the digital cross and right analog looks like its uncomfortable to use, it could need the handles on it to make it better.