A work in progress:

These are the 7-port hubs from MCM. As you may have already noticed, these are just the generic hubs from China that's all over the Bay and sold dirt cheap albeit with less capable AC adapters. All MCM did was couple the hubs with better power units and marketed them. I could have done better and further reduced the per port cost if I had put them together myself but I was in a jam as I was expecting more miners to arrive in a couple of days and I only have so much USB ports on my rigs. I had to pony up for a 2-day shipping and for the applicable sales tax though which added a little to the per port cost but it's OK because I already ROI'd those extra expenses.

MCM's site specified that the AC adapters are 5V 2.5A. I then called tech support to verify the specs. The gentleman literally called their warehouse while putting me on hold and came back on with the good news that it is in fact, a 5V 3.5A. Here's a confirmation:

It supports seven miners with no issues; tested it for a few hours. With all seven BEs hashing, the power units get very warm (an optimistically good indication that the internal heatsinks are doing their job of dissipating heat through the case) but one could still touch them for the longest time and not experience any burning discomfort.
The seven BEs registered 21W AC off the wall on a Kill-A-Watt while mining (100% load or thereabouts). That's 3W AC for each miner. Based on the BE's specified rating of 2.5W DC, that puts the AC adapters' efficiency at around 83% at 100% load; at 50% load (peak) it would probably be at least 85% efficient. That's impressive for a wall wart. If I'm not mistaken, this falls within the 80 Plus Bronze category.
I'm expecting a few more miners coming in on Monday and I intend to max them out and populate the two rear ports on each of them. Here they are in action:
http://s1330.photobucket.com/user/visdude/media/MVI_0076_zps911be64e.mp4.htmlExcellent post. This is exactly the same plan I have. I recently bought 4 of the MCM hubs, and confirm they have 3.5A power supplies as sold on the Bay. My local electronics store has them for ~$7 each.
Two of the ports are in the back, in the opposite orientation. Is there enough room to use those ports as well? Are you actually able to get 7 miners on each hub? In your picture it appears you are only using the front ports.
Nice setup.