Their availabilty was scarce a few years ago when the cowboy boom was going. Especially ones that would shoot the the 38 Spl.There should be plenty of them. You probably will not see a bunch on shelves or racks. A 24" Uberti 1873 "Sporting Rifle" (or the Border Deluxe) with pistol grip, checkered stock and fore end will run about $1200.00 msrp.
Most of the cowboys order them and have them shipped to their favorite gunsmith. They are out there.
Tommygun, the Uberti 1873 will easily handle the 357 mag. The factory 45 Colt is easily handled also. The +Ps will begin to wear the main toggle pin.