To me, the R45 felt a bit more like a Commander/P7 size gun - I could actually fit my palm on it, but it was quite compact.
It is one of the best feeling guns I've ever held, and I'm looking forward to carrying it as a belt gun - and probably shooting it in Steel Challenge - maybe action pistol.
If you want a pocket 45, there was a 5+1 XDm at the SHOT show - about as small as a 45 is going to get. It will be cheaper than anything anyone else is going to make in that category. I have no desire for a 45 that small. My father offered me his PM45, and I had no interest in that, either. (A G36 isn't too bad, but not much different than carrying a Commander size 1911, for someone my size.)
IMO, the pup is about as big as a pocket gun should be. I have some pants w. very large pockets, in which I used to carry either my P7 or my 329 NG, until I put myself on a timer.
The pup can be pulled pretty quickly from a pocket, once it's "pre-staged" (loosened from its holster), even w. my freakish meat hook hands. I could not pull the larger guns cannot be ripped out of the pocket as fast, w.o. running a strong risk of a snag.
Essentially, there are 4 sizes of gun:
Micro - NAA minis, etc
Pocket - Pup, P3AT, Seecamp
CCW pieces - most everything called "compact", etc.
Full-Size - competition, duty pieces - things people tend to think are too large to carry, but which many people can carry w. the proper belt and holster. (Sometime, place a 2.5" barreled revolver on top of a G17 - one is thought of as a carry piece, the other is thought of as a duty piece, but there's almost no difference in size.)