I reckon in the Melbourne south and eastern inner city and inner suburbs (say within 12kms of the CBD) the average mortgage would be up around the $800K mark. When you consider that you can't get a house (even a small 2 bedder) in most of these suburbs for under $1 million I think there would also be a lot of people with a lot higher mortgages too. But, chances are they're earning the big bucks so can service those sort of mortgages.