That makes it a little bit harder. If you didn't have so many projects I'd say break out the welder and some 20-24ga and make one, probably wouldn't be as heavy as you might think. Something like this isn't all that hard, especially for a body guy, just time consuming. That and being afraid to run it hard for fear of messing it up is the other drawback to a metal body.
BTW that's 1/4 scale with a 100cc engine. But you can see the simple shapes and how they are put together pretty good on this. Came out good for a homemade body IMO.