My serious choice will be a 5D (or 5D2 or 6D) + 24-105L if Canon. If you want to go for Nikon, a D700 + 24-120 VR.If you can get that for the OPs $800 in Australia I'm with you. But I believe even used it's a little bit out of buget.
I'm an expat that lives here in KL, Malaysia. I can get a used 5D + 24-105 at around RM 2600. That would be around 850. If OP's willing to extend it a bit, I know it's possible. There are some online stores here that allows staggered payment through credit card. I can recommend Shashinki if you can find what you're looking for in there. They give some kind of 1 week to 1 month warranty which I think is good for used equipment. I mean, the OP is spending some money, maybe it's better to spend it with something you would really want for a long time. Sometimes, if you want to be really happy, you will have to go for that extra mile.