Try Rustfree Auto Parts Co
Address: 88 Williams Boulevard, Fairfax, IA 52228
Phone #: (319) 846-2220
When I had my '77 Step-side, I was looking to replace the complete bed. They had several to choose from in varying degrees of rust. They priced a complete step-side bed with "some" rust for $600. MUCH better choice than Dougs 4-Wheel Rip-offs.