If Ponting misses the Boxing Day test, given his current run and the passing years, it might be time for him to turn the number five slot back into the 'skipper and proven batting great' position, much as Viv Richards and Steve Waugh did at the tail end of their careers, and come back into the side there.
It would remove some pressure from Ponting, and allow Michael Clarke to shift, breaking the stasis in a line-up that doesn't quite seem to fit together any more. Clarke obviously needs to move up, Watson will ultimately move down. Hussey could shift to three until his exit, North is expendible - there is a new generation waiting now, and he, Hussey, Katich and Punter are all into their 30s.
Transitioning towards the Ashes, Australia could line-up:
Marsh/Marsh/Klinger, whichever young blade is making the noise