Yesterday we figured out a nifty space-saving way to mount these, and I'll post a pic tomorrow night once I put the memory card back into my camera so it will save the picture
Take a 1/16" wall angle aluminum piece that has 2.5" legs (hard to find I know, we had to cut metal meant for another purpose to get it), drill holes that are far enough up and apart so that a Jaguar can be vertically mounted to it. Then, mount the Jaguars back-to-back on the mount -- but -- rotate one of the Jaguars 180 degrees on the axis that's normal to the mount plate. This will put all of the motor outputs on one side and all of the power inputs on the other. Then, using either a 3" #8 bolt & nut, OR a #10 2" machine screw, you can screw the Jaguars to each other. For a production mount piece, you can mill out unnecessary metal from the middle and still maintain the rigidity.
WARNING: A #10 machine bolt will thread the inside of the holes. We haven't done shock testing yet with this setup, so YMMV for longevity of the mount.
Other than that, your power distribution block will need plenty of room on each side! This isn't room for wiring, no, it's room so that you can horizontally put a tiny screw driver in the slot in order to take a wire in or out. You can't do this from the top of the PDB, nor really effectively at an angle. The PDB was the single deciding factor in the majority of our preliminary electronics layout. Could someone point us to an effective tool that has a flat 90 degree tip, to alleviate that problem?