I don't have anything new to offer on the topic, but I just wanted to tell you -- good luck with rush!! I hope you'll tell us all about it. Madison is such an awesome town, and I'm sure you will have a blast!
Oh, if anyone is wondering, I just checked the web page and UW -- Madison has the following NPC sororities:
Alpha Chi Omega
Alpha Epsilon Phi
Alpha Phi
Chi Omega
Delta Delta Delta
Delta Gamma
Gamma Phi Beta
Kappa Alpha Theta
Kappa Kappa Gamma
Pi Beta Phi
Sigma Delta Tau