I was looking to do a similar thing - however I'm yet to find a way to do it cheap enough to make it worthwhile for me. As silver is 350 status credits, and at the cheapest rate that status credits can be clocked up at the moment is around $8 per SC, you'd spend about $2500 - $3500 just to get the 350 or so status credits.

QF has "boomerang" passes and similar that would allow it to be done pretty cheaply but you can't buy them unless you have a ticket into Australia from outside Aust/NZ, and also you need to have residence in a different country.

How long do u want to stay in each airport / City? Are you just happy with seeing the airport, or do you want to spend some time in that town?