This simple wooden rack, made on a CNC machine, does the trick. It keeps the stack in a compact and portable package, while allowing cooling air to reach the power supplies.
Step 1: Making the Pieces
The parts are cut out of plywood. I used 1/2 inch walnut-veneered fir plywood. The design is attached as a Corel Draw file and also a .EPS file. When doing your CAM, cut outside the individual pieces, and inside the elongated ventilation holes. All cuts should be done with a one-eighth inch cutter, and should go all the way through the material. The files have six of each part, to make three complete racks from one sheet of plywood two feet square.
Step 2: Assembly and Finishing
Test the fit before gluing. I made the fit deliberately tight, so the racks could be used without gluing them, if desired. You will find that if they are just a little bit out of alignment, it won't slide together. Sand the mating surfaces if necessary.
Because of the tight fit, I was concerned that wood glue would seize up before I had enough time to get everything assembled. Therefore, I used 30 minute epoxy to give myself more working time. Apply just a little bit on the mating surfaces so that no glue squeezes out when the parts are slid together. After the parts are assembled, set the entire assembly on a flat and rigid surface covered with a sheet of wax paper while the glue cures.
It's not necessary, but I decided to make mine dirt-resistant by giving them a light coat of polyurethane finish. In order to hold the assembly while brushing on the finish, I cut a notch and drilled a hole in a piece of scrap wood, and bolted it to the rack. After painting most of the rack and letting it dry, I removed my temporarily handle and applied finish to the remaining spot.