Um, where has this been all my life? https://www.rkguns.com/armscor-vr60-standard-12-gauge-semi-automatic-shotgun-601-bc.html
Yeah, that is pretty sweet! Good price too! I think if I was going that route that I would also look at the Kalashnikov KS-12 which I hear is a big improvement over the Saiga-12. Both have known feeding problems when shooting trap and skeet loads but other than that (and that problem might be resolved now) they shoot everything else well.
Neat Idea, but overthought and over done! Still prefer my Saiga 12, rock solid, dependable with a well known and proven action and familiarity makes it the go to semi auto fighting shotgun!