H-Squared's product isn't terrible by any means, but I see it as phase 1 of at least a 2 or 3 phase solution. If you were running one shelf of Pros in a rack, it wouldn't matter much -- but at 10 racks of 88 Pros each, you'll run into cooling issues unless you put more work into it.
On the topic of density: our chassis was originally specced to support 6 units rather than 4. I vetoed that because it would require a second top-of-rack switch, and would have been too power dense for our current site design.
44 turned out to be the magic number this time around. The design is also flexible enough that if the specification changes dramatically in future Mac Pros, we can tweak as necessary to achieve ideal density.
On the topic of density: our chassis was originally specced to support 6 units rather than 4. I vetoed that because it would require a second top-of-rack switch, and would have been too power dense for our current site design.
44 turned out to be the magic number this time around. The design is also flexible enough that if the specification changes dramatically in future Mac Pros, we can tweak as necessary to achieve ideal density.