The light is a 400w HPS and the fan system is two muffin fans blowing out from the light. There is ducting connected to the fan and that is ushered out of the room. We also have a fan bring air in. The fan system actually cools the light a little bit so we can put it closer to the plants.

And as for the cfl reflectors, we had some homemade ones, but they were more trouble than they were worth (and we were still getting good growth without them). But that is a good idea with the pop cans. I'm working on getting a 150 watt hps to run 18/6 in the veg room. It only gonna be fifty bucks and that should cover a couple small plants and the seedlings can have the cfls.