Purely my (unprofessional) opinion - 95% of an electric guitar's sound comes from the electro-mechanical bits - strings, pickups, nut, bridge. That said, the structural elements (neck and body) can alter the characteristics a bit, such as the sustain or sympathetic resonance. But there seems to be very little actual science out there. It seems that anyone with the resources to do it probably stands to gain more from using timber choice as a marketing tool.