I meant to mention this in my first post but totally forgot. How set are you on a .40? A whole new world opens up if you consider a 9mm? I'm no expert on calibers, so I won't sit here and lecture you on them, but just purely on an option basis, considering a 9 really changes the game.
In what way does it 'change the game'?
Im not necessarily totally invested in .40cal my wife carrys a cw9 and I have a FNX40
so either would do. I intend on concealing inside my right side or backside.
I would HIGHLY recommend a Smith and Wesson M&P .40 compact. I am a gun dealer in Denver and have shot or owned every firearm mentioned in this thread so far, and I am a very strong supporter of Glocks and M&P's. My current daily primary carry or backup carry is the M&P 40c. Handles the recoil well, ultra reliable and priced well. I wish I could get more in stock. I do not feel the loss of capacity of the .40 Shield is worth the size difference from the compact.
Edit: I pocket carry it as well with a Desantis Nemesis pocket holster, part# N38BJE1Z0
Going with a sub-compact, the single stack is the way to go.
Concealing the G27 was about the same as concealing the G23.
If you can hold out until you find a Shield 9, I think you will be very satisfied. I love mine, although I also love my Shield 40. The Kahr CM 9 I had shot well and functioned great but the magazines split down the back side when I had mine.