Hi all,
Just to update on my experience. I pushed my interview/test date back to September (from original invite in April) and flew back to Melbourne for 3 weeks to do test and wait until I received formal approval. I took as much evidence of my intention to return to Australia as I could think of - including bank statements showing I'd left my savings there, statements showing I'm still paying into my Superannuation fund in Aus and a copy of my US visa showing it's a temp visa. I also changed the address on my Vic drivers license and bank statements to a friend's address in Melbourne.
At the interview I was asked to explain why I was living overseas and convince them I was returning to Australia and doing so relatively soon (I think they're ideally looking for within 3-6 months, i.e. you'll be living there again by the time you get the ceremony invite). Honestly, I think a lot of whether you get approved or not depends on a) the reasons you're not living there at the moment, b) how much evidence you can bring to show your commitment to returning and c) who you happen to get as your interviewer. I was very fortunate that I had someone willing to listen to me, review all my documents and take my personal circumstances into account - in my case I have every intention of returning once my current work commitment finishes and I was able to clearly explain myself and provide enough evidence. Interviewers seem to have a lot of discretion so whilst my experience was positive, I don't think it's a given that everyone will have the same experience.
My application was, thankfully, approved and the confirmation was sent to my friend's address in Melbourne, had I not been able to provide that address I think I would have had more trouble getting through the system as the interviewer said only having an overseas address on file usually means you'll get an email asking for a return date before they'll approve you and get you in line for a ceremony date.
I am waiting on an invite for ceremony, which I'm expecting to be sometime early next year, and will have to travel back for about a month to do the ceremony and get my passport.