You can get carbon fiber enhanced PLA, but you get short fibers. [Stefan] glued long pieces of carbon fiber exactly where he wanted them using epoxy. This method did provide some benefits.

The high amount of carbon fibers makes this material extremely ... which itself is already a tough material and lies about half way between PLA and ABS in terms of temperature resistance.

Some parts were made from carbon fiber nylon, a lightweight and robust material with a sleek surface finish, for strength and durability. For less critical components, matte PLA filament was used.