[link]http://stansfibertech.com/[/link]
[link]http://www.precision-fiberglass-prod.com/[/link]
[link]http://www.fiberglassspecialtiesinc.com/catalog.htm[/link]

Between the three listed above is probably the best place to find fiberglass cowls. If they don't have exactly what you need, they may have one close. Or give them a call and see if the can get you what you need. I can't speak for all of them, but I have called Stan's Fiber Tech a few times. They always seem like they will bend over backwards to help solve problems. Give them a try.

Hope this helps

Ken