none of the USPs will have a smaller grip... you need to step into the "p-series" pistols which have only been out for a year or two...
for a CC weapon, either a P2000 or P2000SK (sub-kompact) is your best bet... they are designed with this purpose specifically in mind, and they have a choice of serveral backstrap pieces to custom-adjust the size of the grip. I use the larger SK backstrap, and the medium P2000 backstrap, and I don't have big hands at all.
those are each available in 9mm, 357sig, and 40S&W.
the P30 is more of a duty/combat pistol. it has multiple backstrap pieces as well as sideplates for the grip and is just overall a meaner-looking piece. it is a "full sized" pistol, and its sibling P30L is identical with just another half-inch of barrel and slide added on. they are ONLY available in 9mm and have 15rnd magazines (the P2000s vary... my 9mm SK will hold 10).
I'm hoping to add a P30L to my collection, but will likely settle for a P30 and then buy an extra P30L barrel and have it threaded for a suppressor.
if you any other questions or want to try mine out, drop me a line!