Here's our 7 card 290x monster rig from Ninja Group Buy #4. It's a rack mounted tray design meant for deployment into a data center cabinet.
Very interesting. I'm also working on a 4U rackable case for data center hosting, but I've doubts about temp and ventilation. I'll post pics of our prototype tomorrow.
Could you please post hash rate and temperature, when multiple cases are enclosed in a 19" rack?