I started by finding what little information was available for modeling many-to-many relationships with DB_DataObject. This forum discussion was helpful, but ultimately only gave me information for fetching m=>m links and failed for providing insight on how to get DB_DataObject_FormBuilder to cleanly do many-to-many links.

If any of you know of a way to do this.. feel free to post it to the pear help list http://pear.php.net.