Awhile back I tried to make a crude mold using expanding foam and plaster of paris. The end result appeared as if I had done exactly what I did, simply put, it looked poopy. I have been barking up this tree for along time. Our only hope is if we get a small group order.
Here are some shops dedicated to making fenders
http://desert-industries.com
http://www.fiberwerx.com
http://www.flared-fenders.com
http://www.hannemannfiberglass.com
http://www.perrysfabnfiber.com/
Awhile back I talked to a fiberglass shop and they said they could make a mold if I sent in my fenders, and if I remember correctly the cost wasn't super high. The only problem is finding enough people with the same fenders to do it.
~Brady