I just used marine grade teak plywood with flat black formica on the face. That's for the new nav station. Where the old electric panel used to be I used a surface made of PVC bead board and mounted the new electrical control panels and switches on top of that. I also went to great pains to make sure no flammable material is within a half inch of any electrical contact, whether 12 Volt or 110 Volt. I highly recommend PVC bead board for use on a boat. It is water proof, rot proof, does not have to be painted (ever) and does not conduct electricity. It's light weight, highly flexible and small repairs can literally be glued in place using ordinary PVC cement as a plumber would. Here's a shot of my new PVC ceiling. PS: PVC is very inexpensive and you can buy it at places like Lowes or Home Depot.