Checked in to the AC Accelero X1? I believe that would fit and would do a hell of a good job to boot!
If that doesn't fit then the NV Silencer 6 should as Inno3D use one on their iChill edition 7900GS, also a great cooler.
Asus Sabertooth 990FX | AMD Phenom II X6 1090T | 16gb G.Skill Ripjaws X DDR3 | Thermalright Silver Arrow
2 x Sapphire HD 6870 1gb CrossfireX | LG 10X Blu-Ray Rewriter | PCP&C Silencer 750 Quad | Fractal Design R3 Case
60Gb Patriot Pyro SATA III SSD | 1Tb WD Black | 3 x 2Tb WD Green | 2 x 360Gb Seagate Barracuda