Aye! For a second there I was afraid that some tubby train-spoter was about to hijack the forum and spend the next 25 years telling us all how QF sucks, and how everyone should fly United.
Coz the United programme is the best in the world, and as a *A elite you will get a nob polishing every 2 hours by a gorgeous hostie regardless of your class of travel - just because United is that damn good. Nothing but Grange or 15yo Hunter Semillon served with your Wagyu fillet or Atlantic Salmon (fresh that day) on United.
Did I mention that United are so cool they PAY YOU to fly with them? Seriously, they're that cool. The only airline that comes close is KLM - they only lose out to United because they offer blonde hosties only - if you like a brunette doing the polishing, you'll be disappointed.
Seriously, it's true. Just search "united" on the QF forum @ Flyertalk - you'll all soon see that I'm serious, and you QF fools don't know what you're missing out on.
You can get a *A RTW ticket in F for just 50 points if you're a United elite.
But I digress.....
I doubt you'll see "premium economy" in QF anytime soon - except perhaps in the new big Scarebus - plenty of room in that cough for a 4th cabin class.
I suspect that if they get a 777 ETOPS (Engines Turn Or Pax Swim) to do SYD-LHR non-stop that it will be J/F only. You'd have to restrict the Pax numbers to keep the weight down, and if you start cramming sardines down the back you would have to fly with half the seats empty.
Certainly enough demand on that route to run such an aircraft in an all-premium configuration.
As for "premium economy" on domestic - forget it.