The E-767 is an AWACS aircraft
based on the Boeing 767
-200 airliner. Essentially, it's a replacement for the E-3 Sentry
aircraft, which is based on the much older Boeing 707
platform. The E-767 combines the advanced electronics of the E-3 with the increased capacity, range, and fuel efficiency of the 767.
As with most insanely cool gadgets, the only place you'll find the E-767 is in Japan. Four have been operated by the Japan Self Defense Forces since 1998. While Boeing has shown interest in selling more, the global market for AWACS is a rather small one: only NATO, Japan, and Saudi Arabia operate U.S.-designed AWACS planes, and everyone using E-3's seems to be rather content with keeping their older equipment.
As you might expect, the E-767 doesn't have a production line of its own. Boeing took stock 767's from the line at Everett, Washington, and ferried them to Wichita, Kansas to set up all the cool detection equipment. The refitted aircraft were then sent back to Seattle to get radomes bolted on and finishing touches added.
Boeing hopes to use the E-767 as a stepping stone to other military applications for the 767 airframe: tanker, transport, and the like. Eventually, they hope that the 767 will assume the same jack-of-all-trades role currently held by the aging 707.