I am sorry to say this, and I hope there will be changes before the game-on, but as of right now, there are no pumps for rent. I already called EMR and got the bad news.
BUT there are going to be other Paintball Marshals out there and some of them are ready to loan you a pump as long as you are willing to put up some kind of security deposit.
Paintball Marshals Thread
I'll keep anyone informed of any changes before the Game!