As an AA PLT who shudders at the thought of 50% miles for QF-coded flights in economy for the 20,000+ mile round-trip journey from MEL to JFK, I'm also interested in booking AA codeshares.

A few weeks ago I was looking at the LAN website and was able to price out SYD-LAX-JFK (all QF-operated, AA-coded) for a few hundred dollars less than what the US AA website was pricing. Although having just looked at the UK AA site, that seems to be giving fares in line with the LAN site.

The LAN website AFAIK doesn't allow you to specify any city, but rather uses a drop-down menu to select from, so MEL and other Aussie cities weren't included. I thought LAN may price SYD-AKL-SCL-JFK, so I was surprised when it gave me all non-LAN operated or coded flights.

But still, the cheapest flights seem to be on QF-coded ones.