Sega Genesis Electric Guitar
The Escopetarras: Gun + Guitar
Partnering up with musical instrument craftsman, Luis Alberto Paredes, he has been creating the instruments ever since. Initially made out of Winchester rifles, they are now made mostly from everyone’s favorite Cold War assault rifle, the AK47[Source]
Touchscreen GuitarPhil decided to install a Kaoss Pad directly onto his guitar. First, he needed to find a guitar with enough space on the body (Epiphone Les Paul Special 2) and then he custom mounted the touchscreen. More information here.
The Kaoss Pad is a touchpad MIDI controller, sampler, and effects processor for audio and musical instruments made by Korg[Source]
How much would you pay for one of these babies? This god of a man sacrificed his NES, the best system evar, to make a freakin' awesome guitar. Unlike the Halo fanboy who made the rocket launcher, this awesome project is actually functional[Source 1 - 2]
Face-Controlled Electric GuitarDavid Merrill "mapped the output of a real-time face-tracker onto the parameters of an audio effects processor" in his Facial Control for Electric Guitar project.
A modified real-time head-tracker communicates via a TCP/IP socket connection to a custom server program. The server manages the mapping of sensed gesture onto control messages, which it sends to a guitar effects processor via MIDI messages[via Source]