It seems to me like the best way to go, is to get the 120mm fan that provides the most flow, then add the mod to quiet it down. Otherwise what's the point of quieting a low flow fan, or at the other end, how are you going to get more cfm from an ultra quiet unit?
I say: stay in control!
Now of course to be more accurate, i'd have to draw a chart of noise/cfm, and pick the one with the lowest ratio, that's still in a high flow rate.
BTW, Delta now makes a triple bladed fan, but I have no idea where to get one. Check them out at
www.deltaww.com