John Noveske and CMMG both sell 14.5-14.7 mid-length gas system barrels, and of course the usual custom barrel makers. There may also be others I am not aware of. The mid-length gas remedies the problems that the carbine gas would have. Be it it's more violent cycling, bolt bounce, higher pressures, recoil, extraction, etc. If you do a search, there are numerous detailed posts on the benefits of the mid-gas from the gurus here.
Again, my choice would be a 14.5 build. Looks better, feels better, handles better. If you think about it, the issue regarding the perm. attached muzzle device is really not a problem or PITA. Just decide on which device you like best and leave it alone. I have 10.5, 14.5's, 16, and 20 inch guns. Not once have I ever taken off any of their muzzle devices.