E Glass Fiberglass rolls arent that expensive...
http://www.shopmaninc.com/cloth.html#sglass
Scroll to the very bottom of the page, and you can get three 50 yard 12" rolls for $68 bucks. Thats a steal!
The Polyester resin runs usually for 120 for 1 US gallon, and MEKP catalyst usually runs for a few bucks a bottle...and 3 drops for 1 cup or resin is all you need. It shouldnt jack up prices that much, but Im just throwing that idea out there.
http://www.fiberglassflorida.com/catalyst-mekp.html
http://www.uscomposites.com/polyesters.html
If you were just willing to sell the cut cardboards, the end users can have this option at the very least...even better, is that after its all said and done, one could have the option to paint it with enamels to their liking.