Chris,
To my knowledge, Smith & Wesson is the only manufacturer currently producing a 45 ACP double action revolver.
Since your not really taking business away from any other manufacturer, I can't see where you have an option but to buy a new or used Smith.
I presume the reason you want a 45 ACP revolver, is ease of handling a firearm, using a cartridge you already have on hand, or currently reload?
Otherwise, I'd recommend one of the Ruger Redhawks in 45 Colt, or even the Ruger Blackhawk single action convertable, that shoots both 45 Colt, or 45 ACP, with the change of a cylinder. Cocking a single action revolver, is no more trouble than thumbing a safety on a pistol.
Bill