Well, Shimano has finally launched a carbon crankset. The word was that they had been testing carbon for years, but they were not satisfied with its strength-to-stiffness-to-weight measurements. Evidently, black is the new black. Shimano puts the weight with BB cups at 709 grams with crank arms lengths: 170, 172.5 and 175mm. The FC-7800C is slated for delivery in Spring 2008.
http://www.bikeradar.com/news/article/shimano-launches-carbon-dura-ace-crankset-12255
