G19 with the grip chopped to G26 length. Gives me a little more sight, a rail, and ability to use a 10rnd mag (a whole lot smaller) so I can bend more actively and even pocket it. I could then use a 15rnd mag and grip spacer (with some custom work) for the full size carry.
I'd be almost as happy with a G26 but if I'm this limited to 1 gun, I'd go all in. The reality is that I'm really only doing this for the rail (1 gun and unlimited customization budget constraints).