Very Cool! Love the "saber-tooth deer". Quite pleistocene looking.

I have one of those 94 trappers mentioned in 44 magnum.
Taken deer with it. Very handy to lug around. The recoil is much greater than it's 30-30 kin.
Prefer however the 92 action for the revolver cartridges. Much slicker and more solid.

In my mind I have designed a modern version of your gun to be a little brother to my 60cm. 444 Rizzini DR.
It would be 16 or 17" (to make sure the game warden knows it's not less than 16") and chambered in 445 Supermag.
Longer barrels are not really needed anyway with the revolver cartridges.
Plenty powerful enough for anything around here.
I have done a lot of load development over the years for the 44 supermag.
I was an early adopter in the days when we cut down 30-40 and/or 303 brass and stuffed 44 bullets in.
Then Starline stepped in and made brass although no guns are currently available off the shelf.
What I have in mind is a double barrel version of this (but without the full-bull barrel):

Does it qualify as a Howdah rifle?