[Sabre66]

I'm planning on replacing the wooden seats on my Sabre with fiberglass. I've done enough glass work to know that it's hard to get the true 90 deg bends I need (without a vacuum bag) by laminating over marine plywood.
Does anyone know of a suitable material that comes in 1/4" thick sheets that can be epoxied, machined and painted? I originally looked at using G10, since I've worked with it before, but it's way to expensive.
Any thoughts?