Ahem, excuse me while I put on my flame-proof underwear. There we go.
I'll mention two slim .45 ACP pistols I've owned, and which I liked, and which worked for me. Both were from Taurus. One, the 945, felt like a SIG 220 with ambi-safeties/ambi-decockers. (While the 945 has the option of cocked and locked, you can simply use the safeties as decockers and carry DA.) The other is the PT145. Like the 945, it does have a safety, but as a DAO I never used it.
Taurus seems to have a reputation on the internet for poor QC and CS. I can only speak from my own experience---both the 945 and PT145 worked great for me. (As have the other Taurus autos I've owned, although I'll point out that I don't own a Taurus at present.)
I actually liked the 945 more than the SIG 220 I owned at the same time, and sold the SIG first. The 220 was a nice pistol, though, and I'd certainly not cry if "that's what I had."
All my Kahr experience is with an old flatside steel K9, but I like the idea of the new poly-.45s. The one that really catches the eye for me is the TP45--the 4" barrel. For a belt gun, I find the butt to be more important for concealment than the slide length, and I am instinctively prejudiced in favor of "more running room" for an automatic pistol to cycle.
On a side note, I think we share general preferences in autopistol design: I think the only controls should be a mag release, a trigger and a slide lock, and a smooth double action only trigger. Except for the "smooth trigger" part, that's a good description of my new SW9VE. (Me and the Afghan National Police!)