I like that design primarily for two reasons, it's lighter in weight, and has excellent ventilation without needing to burn holes in the tubs.
I will be altering the design a bit and using pegboard rather than the screen material, and will be using larger Iris CB-110 boxes.
Single stack racks are also easier to put together and move around than racks that hold multiple boxes per shelf. The drawback is it takes a little more material.
Here's a page for Marcus Jayne's ball python rack, it is a variation of the more conventional solid shelf style rack.
http://www.ballpython.ca/The%20Rack.htm
I recently built two single stack racks to hold 7 sterilite 28qt tubs each. I made it out of 1/2" plywood heated with 4" flexwatt.
I needed them in a hurry so didn't take the time to take the step by step pictures I usually do of my cage building. I'm still installing the heat tape in the second one, and plan on taking some pics of it to add to the caging section on my site before I put it into service. Since the actual assembly of the rack is self explanatory, I can demonstrate the rack construction with a few pictures of the finished product.
I hope to begin working on the new racks this weekend. I have the tubs and the materials, I just need the time.