The only legal option, at this time, is something along the lines of:
http://www.artofthehide.com/index.html
The ATF ruled, some years ago that a holster concealing the slide/barrel, or otherwise disguising the fact that the item contained was indeed a pistol constituted an AOW (Any Other Weapon- requiring the fees and licensing). That's the reason you don't see the little Galco Wallet holsters any longer.
Advantages: its a natural motion/draw if someone is robbing you. Disadvantages: none really, as long as you practice, and have a system that works and appears natural. For instance, you'll want to use a money-clip or mini-wallet in a front pocket, for it not to appear strange, having a bulky wallet in back, but never reaching for it.
Edit to add: unless you wear sive 54" waist Levi's, no rear pocket will be large enough for the Kimber.