There were some CZ75 mag AR lowers apparently. I've got an Evo mag one I'm waiting on the upper (has to be a specific wide body sort to accommodate the fat mags) and other parts for.
Got to love a 35rd mag for $19 and doesn't look awful like the Glock mag lowers.
I always liked the pistol addition carbines. Especially now you get get various pistol lowers easily for those that just replace the top half.