I've been looking into some of the other games that people have mentioned and have been able to figure out what we need to do.
I've been able to get Duke Nukem 3D, Star Trek: Elite Force and Unreal Tournament running and online, all with lobby systems and server list. I imagine that other Build engine games like Blood and Shadow Warrior will work the same way as Duke but I haven't looked at them yet.
UT 2004 requires a bit of config to access new servers so I've not figured that out completely yet.
I'm also going to check out both Soldier of Fortune games, Kingpin, Alien Vs Predator, Shogo Mobile Division, SIN and the Jedi Knight games.
If anyone has any requests then let me know and I'll add it to the list.
I'm trying to arrange it so I have everything we need for a specific game in a single download. So I can make that available where necessary.
My one worry though is we get to Unreal Tournament and just never play anything else because it's that good.