Here are some photos of mine. It's certainly a weird beast -- single-shot, single-action only. Modelled on the good ol' Colt single-action .45 revolver, complete with loading gate, ejector rod and all.
And, yes, to the left of the back of the cylinder, you can indeed see a safety catch!
These were sold in the USA with six-shot cylinders in either 22LR or 22WMR, and the cylinders could be bought together and swapped out. The Heritage Rough Rider today looks very similar, and may even be a licensed copy.
Not sure about replacing the cylinder on this one with a six-shot however -- the tone of mforster's reply from Tanfoglio would seem to indicate it's a no-no. My guess would be that there is no indexing/timing mechanism in this puppy, just a cylinder lock. Haven't taken it apart yet except for detaching the cylinder to clean the barrel.
You may well ask -- why would I want one of these? Well, if you live in France and have a lake on your property like me, then you end up with lots of visiting coypu (nutria/swamp rats) that start undermining the banks with their tunnels. Easy enough to pick off with a .22 rifle, but more difficult to dispose of in a live trap. The Tanfoglio will fire 22 Shorts and even 22 Flobert caps (essentially just a primer capped off with a light bullet). Does the job.
It's even pretty accurate with 22LR at 25 metres -- the trigger is quite light, the sights are clear, and the six-inch barrel adds to the gun's accuracy. Still a weird concept, though...