I'm no aircraft interior designer, but on my quick bolt through the dugong, there didn't appear to be a lot more room to put extra seats anywhere with the current 4 class config. Drop it to 3 or even 2 class, that's another story!
kotoyebe...Never underestimate QF .They redesigned the aft galley when they had had the 747 for a couple of years so they could fit more seats in.I'm sure they have alternatives to the current lay out already on the drawing board.
If Emirates and SIA can do it then QF could do it with their eyes closed...
Wait until they sell the underfloor Cabin Crew rest to premium Y/C pax....for a premium $ of course and when they find out how well they sell add some other under floor pallets with bunks as well for a wad of bucks.
The motto with airlines is ..."Never say Never"