Guys, the idea with the originals and reproductions is to hold onto the wrist of the stock with your off hand for stabilization. And no they did not sell well but they were an innovative repeating long gun in the days before inventions like the volcanic or self contained metal cartridge.
Personally, I do not think he has that bad of an idea. The main reason that the reproductions don't sell well is because they are basically a SAA.
A modern magnum design with a swing out cylinder and adjustable sights would be no more impractical than some of the pistol caliber carbines currently on the market.
Give the guy a break.