I live in a town in the south that has around 70,000 people. Last year for the 5s, I went to our only major AT&T store at around 3:00 AM. there were only 8 people there, but they had been there since the store closed at 9:00PM. The store only had 30 phones, so when 7:00 AM rolled around there were about 60 people in line (they filtered in at random times from 4:00 to 7:00), so many of them did not get a phone. The store had 10 of each size.
Hope that helps.