Yes there is; it's called the 1873 Peacemaker, or Model P from Colt. Lots of replicas available in many calibers. You can get pre-made cartridges for it in either black powder or smokeless (use the "Cowboy loads" for the latter). Also, there is the S&W Schofield and the Remington 1875, to list a couple of others; all available as reproductions.
If you like the looks of the old Colts and Remmies, you can get a gun that has already been converted to cartridges, or you can purchase a BP model, then get a Kirst or R&D conversion cylinder for it.
But I'd say, try out the BP pistol first. Learn how to load and use one. You can always make up your own paper cartridges for one; really a good way to pass the time on those long winter nights. Part of the thrill of these old guns is the baggage that comes with them. When you load from a flask or use a paper cartridge, you're able to experience the past in a way you can't do anywhere else.