The NH-U9B SE2 is my go-to cooler for quieting down 4U rackmount screamers, and it seems like you are working with about the same height limitation.
Its a 125mm tall tower cooler with 92mm fans. The fan clips are definitely annoying as hell (I use small needle-nose pliers) but they are very secure once installed. The backplate/retention design they use is probably the best out there.
When I stopped caring about super quiet: E5 1680v2 @ 4.5Ghz, 980ti, i750 SSD - JS9500 & Dell P2715Q for dual 4k@60 because reasons
SAN shares over 56Gb infiniband, microcenter + fleabay = severe risks to my wallet