I bought one of the Pumas in 45 colt / 454. I load "nice hot" 45 colts for it with gas checks. It loads and fires anything you put on it.
For a work gun, you could have it handy with say 4 or 5 45 colts of any power range in the tube, and a stock pad with 454's in the loops.
If you need the 454's, just slip three or four into the loading gate.
If you do decide on this gun, just make sure it is one of the more recent manufactured ones. The older ones had a pin holding the magazine tube that would shear causing the tube to come back on recoil and cause a feeding malfunction. They solved that with the new ones with a tube threaded into the frame.
Also, the point of aim of 45 vs 454 is different, so you should be acquainted with both.
But I have to say, if you want a 45/70 in a small package, that 454 will make you take notice (glad it comes with a but pad).
The large magazine tube definately takes away from the lovely lines of the 92, but a $400 gun that will do all you need should at least be on the short list.
But if you still like the 44/40's I also have a puma in that calaber. It will take 240 gr .430 Kieth style bullets and you can load it very hot.
But for work, Hobie called it ... 45 colt. I add the 454. Small and potent.
The problem using historical quotes in your signature is that there is no way to verify its authenticity.
-Abraham Lincoln
Pair of Colt 73 44-40 (1897)
Parker Bros 10 Gauge (1878)
Winchester 73 44-40 (1881)
Marlin 89 38-40 (1891) Marlin 89 44-40 (1891)
Win 92 38-40 (1892)
Win 92 Short Rifle 44-40 (1901)