I have a small bedroom setup for a studio and his shadow box wouldn't work for me, so I have used some of his ideas to create something smaller. I tried a couple setups, but don't have photos available of those but have pics of my final design below. First, I used an upside down parsons table for the framework so I didn't have to build it from lumber. That was still too big to move around easily in the studio, so I then took a small plastic shelving unit apart and used some of those pieces to create some upward "legs" to hold the top. For both designs to make a top, I used a large frame mounted with a piece of black cardboard, with a slot in the middle for the light to shine through. Still, I wasn't satisfied. On to the foam core board.
I built a box out of black foam core and glued it with an Elmer's Board Mate glue pen -
http://elmers.com/product/detail/E140 I found this at Michael's Crafts near the foam core board, and it works great!
I liked the idea of having the three sides solid to be able to control the light better. I added two cross bars across the top edges to stabilize it. They are glued, but used black masking tape to hold it while it was drying.