Wessel wrote:
Maybe you should build something attached to the bridge of the guitar that vibrates when you strum.
That bit's been done - It's called an acoustic guitar top. A very interesting mechanical amplifier.
You could do something like the Marimba players in CT do for distortion - they use rubber bands to attach plastic shopping bags to the air ports then rip holes in them. The air moving through makes the notes all fuzzy... very cool.
Otherwise look into John Cage's experiments in "Prepared Piano".