I'm intending to build a semi-silent gaming rig with an i7-3770k CPU. Had a NZXT Tempest Evo case in mind for this. To keep the system cool and silent I looked into some options for a silent CPU cooler. I was interested in the Noctua NH-U12P, which I heard good things of, but on further inspection it turned out to be too big for the case I wanted to use.
Does anyone have some suggestions for a good alternative here?
CPU cooler clearance for the case according to NZXT is 134.5mm (it has a side fan).

I'm gonna keep looking into this as well, many of the coolers I've seen so far were too high though and it's gonna be hard getting reviews on those that might fit. But I was hoping someone on here might know a solution that would work.

Are you sure about the clearance? The photos that I've seen of the case show the side fan to be low enough in the door to clear the CPU cooler. Google reviews and photos of the case. Many of them show very large coolers installed.

There isn't a lot that fits within 135mm. See:
http://www.frostytech.com/top5_lowprofile_heatsinks.cfm

If you are dealing with 135mm, You need to try a down draft cooler. Don't forget you need to add 25mm of breathing room which will leave you with about 110 mm of clearance.

Consider
(a) Noctua NH-C14 without the top fan
(b) Noctua NH-L12 with or without the top fan
(c) Zalman CNPS8900 (not bad when turned down)

I would remove the side fan and use a red or blue (different lengths each)
http://www.thermalright.com/new_a_page/ ... _duct.html
http://www.sidewindercomputers.com/th12fandubl.html
to duct in the cooler outside air to the top down cooler.

Or maybe, in the case of the Noctua NH-C14, you can use the side fan as your top fan.

I'm not really sure, that's just what the NZXT website said. It's sometimes really hard to tell how much space you are dealing with on pictures like these. Would have been stupid if I bought my parts and there was no way to fit them together properly.
Right now there is another case on the table for me that will definitely accomodate all the parts. I'm gonna look a little more into whether the Tempest Evo might still be an option before I make the ultimate decision.

Thanks a lot for the anwers!