J&B Access Panels: www.jbaccesspanels.com I think this is what you are looking for. I have made my own from 1/16 to 3/32 plywood. Epoxy mounting blocks made from 1/4 inch Ply and cut a slot for the servo arm to go through. Make a recessed frame between the ribs from 1/4 in sq. stock. Four screws in the corners to hold it in. Works fine.