A few years back Yamaha made an acoustic guitar entirely out of bamboo. It was reckoned to sound terrible, but that was probably because of the top.I agree on the bamboo thing. I have a 6' wide standing desk in bamboo. Rock solid, only 1/2 thick. And very sustainable. I also have a Rack made of bamboo.
Not to derail - but has anyone made bamboo necks before that worked out ok?
Also this thread reminded my that "structural beams" made out of wood with some type of binder are also super strong.
Wood Ears