I found the link abbreviations, and I got it to do this:
[[CASE:CASE-10001]] by using "CASE", "http://mysite/cases/browse" as the
key & url handler.  But, is there any way to do a regexp, so every
reference that looks like CASE-12345 will automagically be url-ified?

I guess what I want is a slightly more magical behavior.  The same way that
e-mailers notice that http://someurl.company.com/ is a URL, and make it
clickable, I'd like some way to make other regexp's clickable.  Any ideas?