Actually, they are pretty cool. You can even use them touring, which is awesome since we tend to always think that metal is structurally superior, not the case when it comes to bikes! Bamboo is also super renewable material, grows fast, is often considered a weed, so why not?! Its light, and super slick, check out a few websites of companies that are pumping these bad boys out!
Bamboo Bike Studio (they are really cool, listened to a podcast bout them, you get to build it and get real intimate with your bike!)
Calfree Design (california based, now these are sexy bikes!)
Perhaps someday I will have a bamboo day! Someday...until that day I will just keep dreaming!