Last week, EK Water Blocks released what they are calling the most extreme fan to date with their EK-Furious Meltemi 120. Marketed for the higher-performance cooling needs, these 38mm thick fans may just be what you need.
I have a half dozen enterprise 120mm fans that draw nearly two amps a piece and are roughly as thick as two regular fans put together. They are incredibly loud... But also outperform 4 fans in a push pull on a 240 radiator by a not negligible margin at less than full power. Small vacuum cleaner level noise. Guess I'm not sure where the selling point is in my case.