You can get Formica at almost any hardware store.
I used Formica to make washers to go between the vinyl upholstery and the window and door cranks. I drilled holes in the Formica with a 2.25" hole saw. I then smoothed the edges of the cut outs and drilled them to fit over the shafts. The washers protect the vinyl upholstery from chafing.
We used plywood "door skins" for the panels. Thin foam was glued to the plywood and the vinyl stretched over and glued on the back side. It worked OK, but I like the suggestions above more. If you do use door skins, note that the plywood bends easier in one direction than in the other. Make sure you orient the plywood the correct way. Of course, we did it wrong.
