AA codeshares on QF metal need to be in conjunction with an international ticket I believe.
Yes, this is the case. You can book something like MEL-SYD-LAX-SYD-MEL, all with AA flight numbers and on QF metal, but it has to go to or from the USA generally to get the AA flight number. Such an itinerary does count, however, towards the four segment minimum. You simply need four AA-coded segments, but don't have to actually lower yourself from QF to flying a plane with "American" or, worse yet, "US Airways" on the side
![Big Grin :D :D](https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/1f600.png)