Really depends on the shape. Im sure you could put together a basic frame with dry carbon pipe, fittings, and a drill.

A complex aero frame is another story. It would involve dry carbon shapes being connected by wet carbon i'd think. Im starting to finally do this now but on a small scale, in hopes to make better shapes.

My only worry is frame strength at the joints with the most stress.

From my experience with carbon, you have to make a couple things and work with it before tackling anything big, like baby steps. But don't let what I said discourage you, i've used carbon and fiberglass for a short time now and still learning. I've made rc car parts, a clipboard, handles, simple aero bars, and a car hood with a kit. Now that you mentioned this, maybe my own frame eventually.