Why not take a shot at a fiberglass body?? Buy some big foam blocks, sit 'em up on your chassis, cut and grind everything that doesn't look like a cartoon car away, surface finish, determine parting lines, shoot it with loud release, shoot it with gel coat, lay up the glass, parting line flanges and stiffeners. Pull it apart, fix any hiccups, surface finish, mould release, gelcoat, lay it up. Let it cure, pull the mould apart, BINGO, something to sell to finance the rest of the project! CARTOON BODIES! the latest fad!
(Of course, you'll still have to cut out the doors, make up jambs and sills, and so on, but that's the challenge isn't it?)