You need your hands to hold the device. So a special gadget would be needed that transforms the mobile into something that looks like a PS Vita so that you can hold both the screen as well as the gamepad. This obviously means that a Wiimote cannot be used. Also, you'll look like a dork IMO walking around with a gamepad on your phone :-/ This might be acceptable for a 16 year old...AFAIK most mobiles provide USB slots which can be used to connect gamepads. Wiimotes can theoretically be connected via bluetooth, however I'm not really sure if anyone tried that or if it's even meant to be supported yet.
Anyway, I already managed to get Dolphin built. The emulator starts up fine, but it doesn't work, games won't launch. Everything just shows a black screen with 0 FPS. Apparently (if I understood correctly) there's some problem/bug with the opengl backend that only affects nvidia GPUs. So using the 64bit package probably wouldn't have helped either... just going to have to wait for them to fix the software. I'll just use 3.5 in the meantime, it at least runs solidly.
Also, about the gamepad gadgets: Sony Ericsson did release the EGB-10 gameboard a few years ago. Since then the technologie has perfected and you can find several brand making such bluetooth gamepads-with-a-smartphone holder (compatible with both android and iOS).