I think the Swiftech Xeon heatsinks would be a good start. With the thick copper base and the pin configuration you wouldn't necessarily have to blow/suck directly over the proc........you could try more of a cross-flow ducted system.........or duct the air in at a 45 degree angle.
Maybe it's time to re-think heatsink design entirely and come up with a design that is just for ducting. With all the talent this forum has in copper machinists, somebody could fabricate it, Joe could test it.
Another thought, I would like to see all the fans at the rear of the case only, a complete draw through arrangement with the proper ducting. Fans on the front always seem noisier. And maybe the fans are something like a high volume, low RPM squirrel cage blower. Axial fans aren't the only way to move air, explore other possibilities.
Take a page from the military, and use sound absorption materials to the line the ductwork.
Just my 2 cents
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Dual 2400MP | Dual 2.4 Xeon
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