
What you are looking at is the first eight
Phoenix Edition Mattson Mini Modulars. Each base system consists of two cabinets that fold together into a little suitcase with a handle on each cabinet. This makes it simple to carry either each cabinet individually, or together latched and closed. This entire system is actually latched together. For each individual system, the left cabinet holds ten modules with a power supply and MIDI-CV converter, and the right has space for twelve additional modules which you can order individually at any time. You can latch as many systems together as you like in whatever configuration as you like.

The system pictured here would consist of roughly 16 cabinets x 12 modules for a total of 192 modules, or 176 modules not including the power supplies and MIDI-CV (the Ms are blank panels). Note that with this setup you would be able to run eight individual MIDI channels into the system - think 8 tracks of modular mayhem.
This image is of course of the reflective logos on back of each cabinet. Note the hardboard backs referred to in
this previous post. The contrast with the logo looks very nice. You can see the custom wood back of Serial #1 on the bottom left. The non-reflective one is mine, Production Prototype #1. All other systems will have the reflective logos and hardboard backs.
BTW, be sure to click the images for the full size shots. You can find a few more in
this flickr set. Click an image followed by the All Sizes link when you get there.
Update: They actually do lock together vertically. I updated the post above to reflect this. Via George Mattson: "They lock together vertically also so the entire structure is latched solidly together. If you look at the unfinished pix of the cabinets (from the front), you’ll notice four squares mounted to the inside of the backs about 1” from each edge. Those are the support spacers for the 8-32 T-Nuts that are epoxied to the back.
On the back, you can see the heads of those 8-32X3/8 screws waiting quietly in the corners screwed into the T-Nuts.
I supply two-3” straps made out of 13ga steel with slotted holes on each end. One of the straps locks the cabinets together when the system is closed. Both straps can be used for structural support by mounting them between cabinets (horizontally or vertically) using those 8-32 screws screwed into the T-nuts in the corners."