You can buy a single VIP ticket. On the Bonnaroo website go to: Fest 411, Travel packages, That will open up a website from Target Sport Adventure. Once on that website click on "Click here to purchase your airport shuttle and travel packages!" Got that far? OK, now click on "VIP camping packages"
Here you can upgrade your single General Admission ticket.
We are also going VIP and my Wifes friend wanted to go with us, she has purchased her single ticket through this. They will also give you the airport shuttle, obviously you you are traveling with friends you will not need this.
I think it comes out to a little more but there is no hastle with splitting a pair.