Didn't make enough poll options, would have forgot that one though (maybe fits under AR: Other, with a HK 416 and ZM 300, etc.) I think Robinson's XCR has a SBR version. Left off the HK51 and DSA OSW though they are even more of the same. Left off the XM 8 and SCAR light, all the next biggest in the line even if under 16", barrels comparable to the M4 (FNC 14.3", AMD-65; AUG is tiny at 14" though). Know I forgot a lot of them.
I dig the K-AC-556, Bulgarian Krinkov, Micro Galil, and the Beretta.