This is a pic of our dry box, basically it is a plywood box using short pieces of PVC pipe set into the sides. Pretty simple and quick to make if you are kinda handy with a circular or table saw. The pipe pieces do not go through the side walls but you could build it that way, just plug the pipe to keep light out.
the other image is a 24 screen cabinet we have made from two sheets of 4 x 8 birch plywood .
mooseman