I was wondering why couldn't the foot well be made completely out of 1/4" hardwood ply with some additional wood strips on the bottom to reinforce it?
I was thinking of building the box like a 'stitch and glue' boat with 3/4" radius epoxy fillets on the inside corners (maybe even add some fiberglass tape)
It seems like this would be quite strong and relatively light weight, since I'm not going to be standing in the foot well anyway.
What do ya'll thinK?

Richard