Oh and I don't know about unlikely. This move has been talked about in individual forms over the past decade (and has re-risen every year since the ABI and SAB Miller formations). In the past it was always halted on the debt load carried by ABI from the buyout, but now that seems to have fallen by the wayside.
What I think would be likely to happen is ABI merges with SAB Miller who then spin off Miller to Molson. That way they get all of SAB M's global markets