I’m not really part of the Jasig CAS Community (learn more), but I do maintain the wpCAS WordPress CAS client and I’ve started development of a CAS server component for WordPress. That project is on hold because one of the products that I’d expected to integrate with it doesn’t use standard CAS and the vendor of that app has chosen to modify the JASIG CAS server to support their apps.
The standard is the protocol, not the server application, though we probably won’t really understand that until we see more CAS server implementations. Nonetheless, it’s important to keep that point in mind if we we hope to grow the usefulness of CAS.