At Cal Poly San Luis Obispo, we explored a variety of ways to integrate some sort of external authentication using a custom PeopleSoft authentication module and settled on integrating with CAS.
Our solution was to write a Java CAS client that would run on PeopleSoft appserver. Using PeopleCode we then instantiated our custom CAS Java client to return the authentication results within the PeopleCode module. We recently gave a presentation on our implementation at the HEUG in Las Vegas.
Check out the following resources
Another PowerPoint presentation on CASifying PeopleSoft 9
A fairly detailed HOWTO is included.
We'll probably present something similar at the next Jasig.