Most of the recommended pistols are fine.
Barrel length shouldn't be less than about 3.75" on this caliber if you expect the bullets to behave as they do in 5" service pistol barrels.
The USP-45C, perhaps due to it's polygonal rifling, produced MVs pnly 5-10 fps slower than 5.25" standard rifled barrels. USP-45C doesn't feel right to some folks, but it's a very nice combination.
If you're comfortable with the Beretta M9/M82FS, the M8045F feels right. This pistol, however, is lubrication sensitive and will malfunction if grease is used on it. Of course, grease isn't called for in ANY pistol manual I've read lately, but many folks think they know better than the factory.
There's one more pistol for this role which is very reliable, yet for some reason is under-rated in this role: Taurus PT-945.
This is an 8+1 .45ACP with the [proper] frame mounted safety-decocker. Can be carried cocked and locked, or hammer down safed, or hammer down unsafed. Same as the HK USP with an ambidextrous lever (HK copied this arrangement).
With it's stock, thin grips it's smaller than the Commander and holds an extra round. The action on this pistol takes very little force to operate which makes it very nice for smaller folks.
Some folks aren't comfortable with cocked and locked, or without a positive safety. This rules out (for them) very capable pistols such as the Colt Commander (or other M1911 type), or any SIG or Glock.
-- Chuck