I've been thinking about this one for a while and then during Thanksgiving break I figured out a hinge that I could make with parts that were laying around. It uses the original screw locations, some aluminum edging, straps and pieces from my kid's old backpack, and scrap 3/4" birch veneer plywood. So far, I've just been running around town with it, but it doesn't rattle and can support plenty of weight. So far so good, but my real tailgating season will get started when the ski resort opens up and I'll let you know how it holds up.