Keg,
Suspect your close to the mark. Won't be till 2018/2019 744 surplus becomes an issue.
Think retirements will take care of any surplus depending on rank.
Having said that I can't see a lot of promotional growth if 8 787 replace 5 744 leaving.
Certainly in the CPT ranks I can't imagine many senior 744 crews wanting to go Airbus and potentially not passing the conversion. Those that wanted to make the switch did so in the last Rin/Redeployment.
So it would be 787 or be close to retirement anyway. Redeployment from 744 to 787 be reasonably speedy Boeing to Boeing? That's dependent on a SYD or BNE base for the 787.