It's not so much what the make, but what they SHOULDN'T make. All of these "fantasy" guns, like that Pietta 1851 Navy Pepperbox, or those .44 navies, or pretty much anything that they decide to make with a brass frame and call it a "Reb" version.
Maybe I'm too much into the historical correctness aspect of the things, but I keep thinking of some poor schmuck buying a "brass-frame 1851 Navy .44 Pepperbox" and thinking he's buying a replica of some rare historical firearm, then, when he finds out what he has, feeling swindled, and writing the sport off forever.
(Maybe it scares me a little, too, that there are actually enough people out there that would actually buy such an abomination to make it worthwhile to manufacture it!)