Carbon or composite shelving.

Hey guys.

I'm trying to track down somewhere that does quality composite sheeting that would be suitable for shelving - 500 x 400 x 3-5mm, not noodle flexy that would support items between 5 & 10kg, and not too expensive.

I've looked at the usual online auction sites but they're usually too small and too thin/flexy.

Any other ideas?

Cheers.