An interesting add here on amart, a US company custom making a CF tube for a C14 for ~500USD
http://www.astromart.com/classifieds...fied_id=660192
A bit more digging and found this site for selling the above and other CF OTA tubes. Looks like its a work in progress ad links dont work.
http://carbonscopetubes.com/
This is the companies normal website for hobby rocket frames
http://publicmissiles.com/