I picked up four of these fans (see the link), they are used to cool/ventilate 8-foot tall computer equipment racks. They are not your wimpy computer muffin fan - they are about 10" diameter. To me they seemed like a perfect stand or canopy ventilation fan for a large tank and have plenty of mounting holes so should be easy to mount.
http://www.comairrotron.com/details_...tNumberID=1241
They have a powercord and grill already installed. I fired them up and and doesn't seem any louder than the 4-inch DC muffin fan I have in my canopy right now - except it puts out 20 times as much air! Serious fan...
Retail for about 75bucks new - I'll trade each one for frags or whatever if anyone is intereted.
-Scott
