G.Skill Ripjaws RAM should, according to a newegg review. They're quite short memory sticks and you should be fine.
I'm also thinking that it would be the same with Mushkin Redline/Silverline/Blackline RAM too, their heatspreaders are quite similar to the G.Skill Ripjaws.
Another possible suggestion is Kingston HyperX - their memory heatspreaders are really short, and you should be fine.
Also, Corsair Dominators fit as well - only if you remove the top section of the heatsink.
RAM without any heatspreaders should fit too.
Noctua even has a RAM compatibility list:http://www.noctua.at/main.php?show=compatibility_ram_gen&products_id=34&lng=en