"International reputation" needs to be more specific. It depends where you want to work internationally.
Within Canada and the Northern US, I think that Rotman probably has the best reputation of Canadian schools. Following shortly thereafter is McGill - not because of its ranking, but because many Americans view McGill as the "Ivey League" Canadian school for some reason.
In Asia, Ivey has a strong reputation simply because they have a Hong Kong Campus. That being said, the Ivey program has lost a lot of its strength within Canada since it switched to an exclusively one-year program. Many iBank/consulting recruiters no longer recruit.
In the UK, Queen's probably has the strongest reputation because of its UK campus at Herstmonceux (sic).
It also depends on industry. For IT/Tech, Queen's is the best. For consulting, Rotman is the best. etc. etc.