No overseas bases - but no reason why you could not commute from Toronto. I can think of 3 of our longhaul pilots already commuting from there.....
With a 'bidline' rostering system, it does help if you have a little seniority behind you though - but that will come with time.....
Why not ask your local BA office in Toronto to put you in touch with a locally based pilot who may be willing to discuss details with you direct? - They know all of the commuters for sure.....