I'll go with one that exists, and I own: Coonan .357 Magnum "Automatic"
Now if we're going to go 'Hollywood' where all I have to do is conjure it in my head and *BAM*, it becomes a reality, then I'll make some changes!
First, I'll clip off the end of my Coonan's monolith frame. Frankly, I don't care for the look. I'd either make it look more "Govt 1911" or maybe go the Hi-Power kinda look with the front end.
Then, we'll get a little crazy. I'll carry two Coonans that look similar, but neither will be .357 Magnum. Rather, I'll have a .41 Magnum Coonan for the heavy work, probably worn in a shoulder holster. Full size slide but with the six inch barrel sticking one inch out of the slide, and Mag-Na-Ported. It'll come out when things need to get "busted up."
My primary Coonan will be chambered in .327 Federal Magnum, and the loads will be blazing 115gr slugs running somewhere around 1,700 FPS. They will hurt and they will penetrate, but the FIREBALL will take out the bad guy's eyebrows also.