I have Cosmix and Ciao! in one of my Rackbrute 6Us as seen below. These two Rackbrutes actually site side by side with the top one sitting to the left so Cosmix and Ciao! are in the middle. This works pretty good for me, but I also now have a Rackbrute 3U which below also which I currently have 18HP of space left (will eventually get the Euroburo desktop enclosure so that will free up more HP but for now this is how its set up.

Thinking I need to add another mix module and wondering what suggestions you might have. Currently looking at the 4MS Listen Four 1/4 as it has 1/4" out that I could use once my new MOTU Ultralite MK5 shows up. Ideally however, I would like the flexibility to route out from a mixer in the 3U to the Cosmix if I wanted to. I like the Ciao! but it is odd HP...anybody know of something that might work better?

Here are the two 6Us
ModularGrid Rack

Here is the 3U
ModularGrid Rack

JB