You are going to have to use a Canadian bank for this purpose.
In Canada it is easy to maintain accounts in either USD or CAD. In the US this is very difficult especially for the retail, non-business customer who maintains low (read less than USD 1,000,000) on deposit at the bank.
I was a Scotia customer with my business in Canada but I did not carry a Scotia ATM card so I can not vouch for their ATM coverage anywhere other than Ontario. However, most of the money-center banks allow you access to your funds through some kind of ATM network.
You might find branches of Scotia, as Mtl_Zack mentions in Central and South America but only in cosmopolitan places like Rio de Janeiro, Sao Paolo, Caracas, Buenos Aires, Santiago,, etc. Even then they may have ONE branch in a country and that branch is likely not going to be a retail branch. You might be able to cash a check drawn on Scotia in Canada at a Scotia branch in Buenos Aires, but they will give you Argentinian currency, not CAD.
SRM