There is always a chance you can talk to someone about a business discount in an Apple retail store. If you're using an EDU discount, it's almost certainly not going to happen. $100 off an iPod is what I would have given in my days as an Apple retail manager.
It's easier for them to take a small dollar amount off of each CPU than a significant dollar amount off of the iPod. Try for "$40 off each CPU if you buy 3 24"s plus an iPod. Get Applecare on the machines and it's almost a certainty.