AA: YYZ/YUL/YVR-SYD US$1,177+ RT in PE
 

The LAX-SYD legs are in AA's new premium economy cabin (booking code P) while the domestic legs are economy (booking code O). There is scattered availability in November and December 2017.

Google Flights shows the fares, but they seem to only be bookable on aa.com (and there is a bit of discrepancy in the $ quoted). Examples of actual fares on aa.com for 11/16-11/23:

ex-YYZ -- $1,177
ex-YUL -- $1,186
ex-YVR -- $1,198

Note that this is USD not CAD (considering that they all originate in Canada)..

My mom won't be happy to hear this news; she just flew this route last month on one of AA's older 777s and had to fly in coach. :-/

EDIT: Note that AA has switched to using its new 789s with bona fide PE seats on the transpacific leg.

FYI, you might wanna rewrite your subject line - at first I thought LAX was included in the sale (as a point of origin). Also, curious that fares out of all three major Canadian airports are nearly identical; YYZ and YUL fares are often similar, but YVR is a good 2,500 miles west and not typically priced the same way.