A hardware modder by the name of alpinedelta has released a mod, consisting of a Wii Mote, a Game Boy and an Android phone, here is a quote from the source, followed by a couple of images and a video:
I wanted to play Nintendo emulators on my phone, but did not like the touch screen input. I’ve heard this complaint time and again, all over the ‘net. I’ve seen some great looking commercially produced solutions, but I wanted something more. I wanted to enhance the experience by actually playing on classic Nintendo hardware, and at the same time not having to plug in via USB. Not to mention I love making things.
For more images, check the source:
Game Boy Android Gamepad by alpinedelta
For more mods by alpinedelta, check here: