Oh, Armalite just introduced a model which uses the KAC/DPMS/Pmag pattern (but in their case they are just going back to their original pattern)
Those mags are called SR-25 pattern.
ArmaLite has the AR-10 16" carbine available in both SR-25 and M14 pattern magazines. The pre ban M14 mags are legal in ban states.
The best bang for the OP's buck well be the ArmaLite AR-10A (SR-25) A4 carbine.
Forged upper and lower unlike some others, chrome lined barrel, C158 bolt, under $1500 street price.