I made one, but it was intended to use home-built lenses and standard LF lenses. I got the basic idea from the Alan Greene book and modified it so I could use standard 8x10 holders and a ground glass. The trick is to start with holder dimensions and go from there. I made it with thicker (1/2"?) black gator board (like foam core, but with a plasticy outer layer), hot melt and black duct tape. It worked really well. I don't have measurements, but lots of images of the construction details here.