737-700's I know have how started to become common place having winglets, and these have helped lessen the confusion. But now as stated in another thread WN are glueing on winglets on to their 733's and this is not going to help.
Also I know some of the newer 737-700's no longer have the "Eyebrows" above the cockpit windows, but know many of the oldler ones still have them.
I am familiar with airlines like easyJet that painted the ailrons orange on their 737-700's, and could distinguish these between their 737-300 fleet.
Photo © Patric Borg
Photo © Yu Ming
[Edited 2007-02-18 17:35:33]