The Performance Center guns are basically semi-custom and top-of-the-line 3rd Gens. They are hand-fitted, reportedly very accurate, not very common, and will cost almost as much as 3 CS45's. I believe the Shorty 45 has a compact grip and a 3.75" barrel, though I've seen one listed as 3.5" barrel on the factory case.
The CS45 has a 3.25" barrel and comes from the Value Line of the 3rd Gen family, and has a 6-round sub-compact grip. Overall fit and accuracy will not be as good as the PC guns, but you can usually find one of these for sale on Gunbroker.
Another good option for a compact .45 would be the 457, it's also from the Value Line but has a 3.75" barrel and a compact 7-round grip. Basically a budget version of the Shorty 45 that usually costs less than the CS45.