Are you sure, I looked and found nothing save the fact they would build drag bodies for you?
I'm not a body guy but I've heard Import people doing it for cars with no aftermarket like RX3's and such. It was told to me like this. Lay out your stock fender cover it in wax, cover the outside with a extra thick layer of glass and pull the fender and sand and smooth the inside of what is now a mold. Seal up the inside with something and sand again, because you want your mold to be as smooth as possible.
Be nice up here no more rust worries in the fenders, just pull em coat the chassis and strap on the new pannels but I figure thats weeks of hours of work for even one easy panel, doors would be a bear I think.