Honestly I would look at a Ruger super redhawk chambered in the 454 Cassul.

Even though the Cassul is a real power house of a round the beauty of it is you can shoot 45 colts, which recoil very minimaly more than a 45 ACP, out of the same cylinder and as you grow and progresse you can step into the lighter 454 cassul loads and on up the the real heavy stuff the older you get.

Another excelent choice would be a S&W or Ruger chambered in the 44 Rem mag. Same thing about the 44 special loads applys here as it does to the 45 colt above.