Just read an article about a new material developed by Nanotechnology - nanotubes.
From the article:
An advance in nanotechnology may lead to the creation of artificial muscles, superstrong electric cars and wallpaper-thin electronics, researchers report.
Self-supporting, transparent and stronger than steel or high-strength plastics, the sheets are flexible and can be heated to emit light.
A sheet made from nanotubes, tiny carbon tubes only a few times bigger than atoms with remarkable strength and electronic properties.
Future applications that scientists have discussed include creating artificial muscles whose movement is electrically charged, or race cars with stronger, lighter bodies that could also serve as batteries, says chemist Andrew Barron of Rice University in Houston.
"We could see this on Formula 1 (racing) cars by next season, says Barron. "This is a jumping-off point for a technology a lot of people will pursue."
Haven't seen any research or strength/weight ratio and how it compares to other material. But if they're looking at applications in the Formula1 cars, why not bike frames?