go buy some used 10 base hubs, lots of them for each dorm. daisy chain them together with crossover cables. and then connect the top hub in your chain to a realy long cable running to a central location (make sure the cable is cat5 and excedes 100m because if u dont, the timing will be off).
then once you have all that setup, youll need net connectivity. may i suggest an oc192, it will definitely keep up with your blazing lan. use whatever router and csu setup your telco provider gives you. but then plug the router to a machine running windows 98se with a 10base cable. and make sure you know how to get ICS sharing. but some sacrifices need to be made. only 253 clients can connect at a time. so u gotta setup a time sharing system. its realy not that much of a problem. you can mirror files locally by forcing every user to install a gnutella client (u have such a plethora of local bandwith, u might as well use it).
if someone tells u that u need to be in a switched environment, ignore them. 1500 clients is fine for a shared bandwith environment. FDDI between dorms, hell no, theyre just trying to get u to spend more money. and remember, if someone tells you a basic fiber gbit ethernet switch will work (5 ports for dorms, 1 for main campus router, and any others for server clusters), just laugh at them.
ohh yeah, never use cisco or nortel products. theyre just expensive and your generic networking equipment performs just as well.