Akdal MKA 1919 is actually a better choice than the Saiga. They are only a few years into the US, but the aftermarket has them running great and there are entire US made guns based on that design now available.
The Origin 12 is still pretty new, but shows some promise. There are three or four in development, prototype or "rough" production that also have some good design features.
Of course, there are the box fed manually operated shotguns, bolt, pump and even a lever either out or in development.