In 1983 I travelled Paris to Bangkok on a Thai 747 where I occupied the centre seat of 5 across. I accept that it probably was something that even the bean counters couldn't justify because Thai don't do it any more and I admit that I haven't noticed it recently on any other airline. It still leaves ABC and HJK on the sides though.
I do remember seeing a 3-5-3 seating plan published during the early days of the A380 development so that is still a possibility. God forbid that an airline actually tries it.
The problem that I have with Premium Economy is that for the extra comfort you get it is monstrously over priced.
You mention EVA Air. EVA is my airline of choice when I fly to Europe 2-3 times a year on business. I now know my way around their cabin layouts (B777 and B747) and when I allocate myself my seat on line I know which ones give you the best space in Economy. I have also amassed a lot of air-miles with them and look forward to some upgrade perks soon.
