I bought an 08 last year with 70K miles in New York and I was searching for a year.
I suppose the folks who buy $60,000 cars don't sell them quickly, and the leases get turned over at Ford dealers. Very, very hard to find them. It's a strange economy right now -- people are unsure of the future and gas is very cheap. The new cars are horribly expensive too and folks have learned that these big trucks give well over 100,000 miles of trouble free service. The Internet has also leveled selling prices: In three minutes you can see exactly what a car's worth and price it in line. Nobody gives anything away.
If you know a private dealer who has access to the Manheim auctions, you can find some there, but they're not cheap and the auction cars are often flawed.
Finally found mine on Craigslist locally and paid good money ($12K) for it. A very clean, well outfitted car but not the steal I spent a year looking for.
If you really want a car, check with the Ford dealers, but expect to pay a premium of perhaps 30%...