Some years back I saw some info on a bike that was made of carbon and Kevlar, I think, and had no seat stays. It had two wavy chainstays, and was made in New Zealand, I think. I haven't seen anything about it in years and I'm beginning to think it was a figment of my imagination. But I thought it was a neat idea, with the chainstays designed to flex to absorb some bumps, while being damped by the fibre. Neat and simple idea that apparently didn't work.