I keep a tab on my web explorer app for support.sas.com, which I use for retrieving tech notes, samples, problem reports and SAS conference papers. However, where you are looking solely for something that could appear at any US SAS conference, then Lex Jansen has a more complete set of papers. I did a Google search on Lex and concordance and came up with the following page.
This is an index page from the online discussion group SAS-L, and Lex is mentioned in one of the replies, presumably as having relevant material on his site. What is even more interesting is that Dave Cassell has provided quite a lot of commentary on the subject. Dave, a fellow SAS curmudgeon, is my number 1 source for many statistical issues and appears to have provided an explanation and a number of clarifications on concordance / discordance.
I suggest you start there, and if you wish to clarify any of his points then post the question(s) to SAS-L. You will need to register on the site before you post.