-
In my neighborhood is a large plastic fabricator and reseller. They stock lots of product, and can fabricate a wide variety of products. They have a remnants shop with scraps. Lots of different materials in different shapes and sizes, sold by the pound, cheap--but you are taking whatever you find. If you can find some place like that near you, you can stop by occasionally and find great deals.
-
My guess is that after almost 12 years, the OP found what he needed.
-
Check with local toilet partition supplier. I've often thought about "borrowing" some from HD bathrooms.