Make it Yourself: Bamboo Bike
Bamboo. Bamboo is one of the strongest materials on the planet. It has 40 times the effective life of carbon fiber and provides 60% more return than traditional core materials. Bamboo has a tensile strength and weight-to-strength ratio superior to steel, yet it is light, flexible, and resists compression. You can make surfboards out of bamboo. You can make snowboards. And you can also make a bike.
How To Make A Bamboo Bike
You can find some instructions here. I am not sure if you can buy yourself a bamboo bike somewhere or is it so far just a product of some enthusiasts but it sure looks nice.