Live anywhere you like providing it is no more than one hour to your gateway. The gateway must also be a 'major' airport.
I have heard of one or two people living further away than this but moving to other accomodation (with family or friends I suppose) the day before they are rostered on so as to meet the requirement.
Definition of a 'major' airport? Not sure really, I think you have to negotiate that when the time comes but lets face it you only have to drive to or from the airport once every eleven daays with the six on/five off roster so it's no hardship.