Hi,
I have written a modification for Moodle that uses the Central Authentication Service that is being developed at Yale. (http://www.yale.edu/tp/auth/) An example of this mod is being used at http://forbin.ics.hawaii.edu/ - If you would like a copy of my modification you can email at <font face="verdana,arial,helvetica,sans-serif" size="2">chris@forbin.ics.hawaii.edu</font>
Requirements: libcURL (cURL itself will work as well)
Best regards,
Chris