Sorry Dave, there is a huge whole in the central Pacific. You can avoid it and fly around it (wasting gas and time) and maintain 180 ETOPS, but you cannot fly through it. I believe there are few other places as well. You can fly a longer route, and maintain 180, but it costs you a lot of time and gas.

If 180 was the longest, why would Boeing and Airbus go to the trouble of certifying (and trying in the 787) their aircraft for 300+ minute ETOPS, if 180 was enough?

West Coast to Hawaii being the longest is a myth, and always has been. Nobody thought about the others before because those routes were exclusively flown by 747's.

I will do some research and post a link.