Well with Alex + team gearing up for the Big Brother finale and showing the "best moments" of the 11 seasons it seems it's almost definitely not returning to Nine, as we've suspected all season. I don't think Ten have the ability to pick the show up this quickly though, perhaps in 2016 but 2015 seems to soon for a network change.
Well Channel 5 in the UK managed to snatch up Big Brother the year after Channel 4 ditched it, so I don't see why not!