New fiberglass ones can be found here
http://www.usbody.com/ I don't think they are a good replacement though. Looks like alot of work, and then it still is not the same as an original steel one.
For the money and time, and work that would have to go in to buying and finishing one you could buy very very nice original and have it cleaned, fixed, and painted for probably the same money. And the you would have the real thing.
