I think Transparent Aluminum would work best. I'll check with Dr. "Bones" McCoy as to the feasibility of a T.A. frameset. Heck, a 1" thick sheet of the stuff held nearly 1,000,000 gallons of sea water and two humpback whales in the cargo hold of a Klingon Bird of Prey. And withstood the force of travelling through time by doing a lap 'round the Sun. I think a properly fitted T.A. bike could support my frame while bombing down some hill.