I couldn't find one that isn't widescreen on Dell's, HP's or Asus' website. Even the old Asus EEE PC 701 (the model that arguably started it all) is widescreen.
The whole netbook format owes its existence solely to the market being utterly flooded with portable DVD player LCDs -- those awful 7" 800x480 screens cost ASUS less than $5 each!