Finally a thread I can contribute to
I owned/ran an Internet Game Center up until a year and a half ago and the previous poster is correct, space is not going to be the real issue because every game server I have every configured only required one installation regardless of the number of servers running.
With that much processing power, your real issue is going to be bandwidth. You might also have issues with IP/Ports because each server for each game is going to want to run on it's own Port and, depending on the number of servers per game, that could get real confusing real quick (this could be mitigated a bit by using multiple IP's).
Your REAL biggest problem is going to be keeping all the wall hack/cheater/smacktards off your servers
Your best bet in this regard is to reward frequent players that exhibit good playing habits with (game) admin rights (not to be confused with OS Admin rights).
Also, although I'm probably speaking to a Linux audience, you should probably stick to Windows for OS if you can because, if you don't, you will have MANY issues related to "we should be releasing the latest update for Linux soon". There's pluses and minuses for each side but we abandoned the "Linux Game Server" idea way back during original Tribes because Linux releases/fixes/etc trailed Windows too much.