I agree with Rick, You can build a very lightweight shell, probably without any internal bracing, using canoe/kayak cedar strip/glass/epoxy techniques.

The trick is going to be to establish the shape you want to build. Working backwards, you will want to bend your strips over, and fasten them to, forms. The shape of the forms will come from either full size patterns (will the manufacturer sell those?) or by lofting the shape. If you go the lofting route there are two ways to go, either the shape is defined in some sort of CAD program or you design it on the drawing board. Alternatively, someone else has already gone this route and can provide you with a table of offsets. Somehow I don't see the manufacturer parting with this information, which leaves you to, in essence, design the shape yourself, either on the drafting table or in the computer.

Another tack might be to carve a full-sized plug out of foam and glass and epoxy over that to make the finished shell.

BTW, I like the shape of the body.