PingBuster let's me mask my WoW IP. I am in Germany, but do a lot of powerleveling for people, as well as leveling arch/grinding honor, and I can mask my IP to several locations in Europe and the US so there account doesn't get IP locked.
Edit: it also gives me the flexibility on my botting accounts to call blizzard and say I was hacked and they restore everything as it was before the IP jump, sometimes that might just coincide with me selling over a million gold, and blizzard helps me recover that gold after I am hacked, if you get what I'm saying.