I wouldn't be afraid to buy one. The basic frame, barrel, cylinder should all be sound. There are plenty of high quality internal parts that would fit or could be fitted, IF you were to have any problems. Lots of good 'smiths out there too that can smooth out any problems. Since it's essentially a used gun (or new old stock) warranty really isn't an issue. I generally fix any troubles myself since my experiance with warranty work is negative.
Uberti's come in all the dash calibers, 44-40, 38-40, and 32-20. Beretta oringinally offered the Stampede in 44-40, then discontinued it, but unsold ones can still be found from time to time. The New Vaquero only comes in 45 Colt and .357, however, considering past history, I see no reason Rooger might not offer special runs in 44-40 or 44 Special at some time in the future.
You also might look at the Taurus Goucho. The catalog lists a 44-40, but I've never seen one in the flesh.