Or, you could simply use the version of the Intel 750 Series 2.5" SSD that has the cable with a M.2 connector on it, rather than the original that has the U.2 connector…
Intel 750 Series 2.5" U.2 (M.2 adaptor) 400GB PCI-Express 3.0 x4 MLC Internal Solid State Drive (SSD) SSDPE2MW400G4M2 - Newegg.com
Would that fit under the mainboard?