Is there really not one person that stands out in your mind as like THE person you would want to bring? Because it would just be so awesome and you wouldn't be able to believe that you had her there with you?
Ask her.
If she says no, or she can't make it, or she has other plans, or she has a boyfriend you didn't know about, then, hey - that's cool. You've got all these other girls you can ask!
I know a girl that could be like this, she's in the top 6, but out of the top 4.