I’ve updated drupal running rnd.feide.no to latest 5.x version, version 5.12. Let me know if you encounter any issues after the upgrade.
I will probably not upgrade to 6.x until early 2009.
The simpleSAMLphp login module actually seems to work better with 5.12. There was some issues with caching of the dynamic menu items (federated logout and login). Now, you will not see logout after you have successfully logged out. Good!