I haven't had to do this since the NT days, but I use to use a variable to represent the DCs in login scripts, %servername%, which would allow the user to draw their profile from whichever server answered the fastest. It's been about eight years since I've used this and I'm not even sure if it will work within a GPO, but it may be a direction to look into.
We have many people who travel to other offices as part of their jobs and the logon experience when they get there is painfully slow. Is there a way to set a policy so if a user authenticates to a domain controller away from their "home office" that they will not receive any policies such as a logon script or folder redirection. Any suggestions would be appreciated.