This is definitely an unconventional technique, but there are several examples of carbon fiber guitar makers - one company close to me is SF based Blackbird Guitars. They use carbon fiber to form the entire instrument; body, top, neck, fingerboard, etc... Mine definitely isn't as polished and professional as theirs, but it was a great challenge that introduced me to a lot of new materials and methods. I'd like to share the new skills I learned along the way with anyone who's interested. Considering this was my first time making an instrument of any kind, and my first time working with carbon fiber, I'm very happy with how everything turned out.
One note before I start, though - there is probably a lot of room for improvement in this process. The workshop was designed with complete beginners in mine, and therefore ignored advanced techniques such as vacuum bagging in favor of simple, intuitive methods. The whole body was laid up and finished with brush and gloved hands. For a very different approach using vacuum bags (which I hope to try in the future) see this other instructable - A Carbon Fiber Violin.
It's really hard for me to estimate the time and money that went into making this, because I was working on so many project at once I wasn't keeping track very well, but I estimate it took me a bit over 1 week, working nights ,to finish the body alone. I'll break down costs later when I list the materials.
I worked on the entire guitar project most nights for several weeks - making and assembling the mold was done in one night. Making the body took another 3-4 nights - it probably could be done in 1-2 nights, but I had trouble with one coat of my epoxy drying - explained later. After taking a break to work on the other guitar components, final shaping, finishing and installing the other components took another 3-4 nights.
Here is my first attempt at a 3D 'catch' model of my guitar. Click the 3D view button on the left to activate the viewer.