I don't know why kinddiesel went off on you like that. Lots of people use 12V DC fans.
Supra's researched this stuff as much as anyone.
I went cheap. I had a few PC power supplies laying around. Used a Kill-A-Watt meter to find the one that used the least amount of electricity at very low loads. I picked one that came out of a 10-year old Gateway small form factor PC. It only used 13W with no load, and about 17 W with several small fans strapped onto it.
When they're inside a computer, a PSU will idle at a very low power setting, waiting for a signal from the motherboard to spin up. When used in an application like ours, you grab the big ATX plug (the big, long, white plug with either 20 or 24 pins) and you jumper the green wire to any of the black wires. Google "jumper PC PSU green black" or something similar for directions. Once you've jumpered the green to black, it'll fire up whenever it's plugged in. If you power the PSU from the same timer that's controlling the LED power supplies it'll all turn on and shut off at the same time.
The yellow wires provide 12V. The red wires provide 5V. So the yellow wire will make those Arctic Alpine fans spin full speed ahead. A red wire will spin them much slower. Maybe too slow.
Supra's 9V option will spin them slower than 12V, but faster than 5, which is probably pretty close to where you want to be.
EDIT: Supra, if you read this - with the power supplies you linked to, I assume you solder, crimp, or use some terminal strips to connect several fans all together in parallel, then connect to the power supplies? Do you have a rough estimate how many 12V DC fans those power supplies could handle?
ANOTHER EDIT, DANGIT: It can be confusing figuring out which wires to use coming off the heatsink fan. Anybody know off the top of their heads which two wires to use on those Arctic Alpines, and which one(s) to ignore?