Network Testbed Emulab.net
gseidman writes: "Have you ever needed to simulate a network? Tired of old ns? Do you just hate dealing with hardware in general? Take a peek at Utah's Emulab.Net. They have over 300 PCs, some StrongARM devices, roughly 5 miles of cabling, a huge and expensive switch, and great software for setting up a virtual LAN. They also have a gallery showing the machine room in various stages of completion (did I mention five miles of cabling?)."
How much does it cost to have them do what they do for you?