I know flying on the -400 is a treat outside of the norm, but the Y class seats get very old and very unfriendly after 45 minutes of being seated. That will give you about 13 hours of being miserable once the romance of being on the 744 fades away. Where as you can be on DL, a tad less cramped AND have on demand video in each seat. Of all the times I have done the LAX-SYD flights, I can easily predict the amount of open seats as of now will likely fill in business class. First class is wide open, but being an offline jumpseater with the wife in tow... forget about it. Another option, what about doing a ZED on QF's A380 and really make the flight memorable?