Shockingly, AT&T processed an unlock for my iPhone 5, even though it's only 16 months old. The fact I have been with AT&T for 13 years and have four lines on my account and a monthly recurring charge of $220 might have helped.
Now, to find a SIM in semi-rural Galilee (well, Tiberias, but headed south along route 90 to Eliat)...