OK, so my original thought was to leave the glass on and put the COBs inside. That would contain pretty much all the heat, but you guys are right. COBs on the outside with proper lenses would be way, way better. I see what you're saying about not bothering with holes. If they're lined up, the heat will transfer through the aluminum sheet and into the heat sink anyway.
Back to the CMH discussion, the Ceramic Science kit comes with a Welthink ballast I believe, which are supposed to be pretty good. You can also buy those mogul socket adapters on ebay.
http://www.ebay.com/itm/262009602511?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT
The Phantom CMH rig is 338 at growershouse + 30 for the air cooling kit. Four of them over my 9.5' x 4 canopy puts one reflector about 5" from a side wall. That might be a tight fit for the ducting, so I'd start with three instead. My setup is three 3x3 drip tables anyway.