If your wife is pretty keen on living in a somewhat premium (for down there) house, then why not rent one down there? The yields are really low so it would probably cost you half the price to rent the equivalent house.
Everyone wins?
Uh you can get a pretty nice selection of properties in halls head for $430k last time I checked. I don't think you would need to compromise on much at that price. (300m from beach instead of 200m?)