Well,
I'm down here in sunny Florida using a local town library computer and just happened to stop in to Pistol Dynamics in Palm Bay/Melbourne and had a long and most informative conversation with Paul Liebenberg, what a GREAT guy.
He showed me the originals of the .356TSW Limited with a 6" barrel with the real high capacity mags and I don't mean 15 or 17 rounders.
Also the original S&W FBI 1076 Test and Evaluation gun that was always referred to when a 1076 was in question for any reason.
It was the one that all the other 1076's were compared to, with 9, 11 and 15 round magazines that are truly one of a kind.
I will show pictures when I return home.
I was asked to not post any S/N's.
Also, on aside note, don't give up on the .356TSW round, all I can say is - IT'S NOT DEAD.
With best regards from sunny Florida, see ya soon,
Bad_Man_One

P.S.
I was told to forget about building a "blowback" .356TSW carbine, the case head will separate.
I'm not the first one to think about it and definitely not the first one to see the results first hand. LOL