oooh, my question is, how do you plan to keep their home directories? Are you going to mount /home via NFS? If so, how do you plan to handle the situation where someone logs in on 2 machines?

Yes - that is a KEY flaw in almost ANY network....When a single user logs onto 2 machines at the same time. I think that If anyone has found a solution to this they should post it here .

I suppose a script would have to be run when logging into X that checks for the existence of another X session. You couldn't put it in a bash login script 'cause you can login multiple times through a console. Now I'm curious...

I think gdm allows a pre-session script to be ran. I suppose this script could check for the existence of an existing X session for this user. Do you think it could halt the login process though? (this would have to be done with some sort of .pid flag as our X server does not have access to processes on the other machines)

edit: I just checked the gdm.conf file and it appears there is a "doublelogin" warning that can be prompted. I wonder how this works. Is it only for the same X server or will it check to see if the home directory is being used by any X server.