DIY step well cover, ideas?

We fabricated one along the design you are thinking of but used 1/2" plywood oversized beyond well opening, furring strips around the edge matching the outline of the well. Carpeted ours. Hinged in the middle using a door hinge. You may want to go a little thicker depending on the weight of the persons using it. Our goal was to keep small grand-children from falling into the well but it made it so much easier to get to the TV and DVD player. Just one suggestion, cut out a space near the door to access the door handle if it would be covered being lower than the top of the well. It still has to be an emergency exit. The cut out made it easier to lift out as well.