Hi there!
What we do at my school is really fun! The big will make two hats exactly the same (one for her, one for her little). People here get so creative with their designs!! On the day of the revelation, the little receives her hat outside her door, then goes to the sorority house where all the bigs are hiding. The little hunts for her big and she knows who her big is because they will be wearing the matching hats!! It's something to defiantly consider.
Good luck!
P.S. I am in charge of making a t-shirt for my sorority. Do you have any ideas for slogans?