Even "souped up", the .45 Colt is still a pistol cartridge, as is the .44 Magnum. Both are underpowered compared to even medium power rifle cartridges like the .30-30.
It is not a matter of range unless you plan to hunt where you will get long range shots; rather it is a matter of power and in that respect, a .30-30 or .35 Remington will have it over any pistol cartridge. Unless your wife is recoil sensitive or there is some other reason for limiting the power of the rifle, I suggest looking at something with more power.
As an added note, both the .45 Colt and the .44 Magnum (and the .45 ACP, .357, etc.) have fans who believe that "their" cartridge is the most powerful the world has ever known and will kill deer at 250 miles on a foggy day or penetrate enemy tanks before going on to wipe out whole countries. The .44 Magnum in particular was the subject of more hype and nonsense than about any other cartridge except, maybe, the .223 Remington/5.56. Until, that is, cartridges like the .454 Casull came along, when they in turn became the darlings of the gunzines.