If you've ever wondered about going beyond a 2 server (moodle + database) cluster for serving Moodle, there's on article up at www.linux.com about how to do exactly this. It's a general article about how to configure a load balancing LAMP cluster, but it's very relevant for anyone who wants to do the same for Moodle.
http://www.linux.com/article.pl?sid=06/04/12/1824235
Reading through the article, it seems pretty easy to do. Perhaps you can use it to convince your school's IS department that Moodle scales easily, and to switch over from Blackboard to Moodle
Lawrence