JDiver

There is no QF flight that goes through to JFK - they have been using two-class aircraft on BNE and AKL flights, three class SYD-LAX-JFK, iirc. And of course, you will have to pass immigration formalities and recover your bag(s) for customs clearance before passing back through security and boarding, even if you are on the through flight.

As tom911 points out, watch those QF fare classes - on some you earn 50% of EQ miles, and on the lowest you earn 50% EQ Points based on the 50% EQM - 25% points, so if you are planning anything like status using points, you could have a nasty surprise. (The 19,900 miles round trip could turn into not getting a Platinum challenge for those who think this is a lead pipe cinch, and for Platinums, you earn 1/2 the EQM and effectively loose the double miles bonus.)

As ijgordon says, you can at least upgrade the domestic portions on AA, assuming seat inventory, stickers / status combination.