I've never heard of a handgun like this.
http://www.slickguns.com/product/smithwesson-governor-41045acp45lc-revolver-609
Made by Smith & Wesson, it's a 6 shot revolver with a 2.5 inch barrel which can shoot any combination of .410 shotshells, .45 ACP or .45 LC. I think it would make a dent in anything one could hit with it.
However, for someone like me it's single-shot. I'm afraid it would fly out of my hand. But what a concept.