xpt
Maybe I am eating confused but to me direct is Mel to LAX and Non stop is Melb to LAX. Mel - Syd - LAX is one stop and a PITA one at that. I'd fly via Aukland before Sydney and Have done so.
Not sure where you get $4k from apart from the most expensive fares.
Mel - LAX return, QF93 and QF94 is sub $2000 if you book right, A380 aircraft. A bit more if you go up a level. Unless you tell me otherwise, that is Qantas. Those figures are for April / May this year, 2 months out.