I have just ordered 3 sqm of 1m wide 12k unidirectional and 3 sqm of 1.27m wide 3k 2x2 twill weave carbon fibre cloth for my 10" f4.66 astrograph OTA upgrade project, the order cost me 261 USD including shipping + $30 in fees for the electronic funds transfer via my building society to obtain my "testing samples".
I could not find anyone in Australia , or in the USA or UK on the internet or Ebay who came close to matching their price.
If you are thinking of making a larger carbon fibre tube , they are worth contacting, they are very approachable even though they are generally more geared to bulk purchases.
The company I bought my carbon fibre cloth "samples" from is :
Jiangsu Yujie Carbon Fiber Sci-Tech Co., Ltd.
Tel：0086-510-8789 1677
Fax：0086-510-8789 2677
http://www.cn-txw.com/
They don't take credit cards or PayPal , but that's not a huge problem.