RBC, Royal Bank of Canada, operates here in the SE part of the US. My understanding is that some of my Canadian snowbird acquaintances bank with them on both sides of the border. They can withdraw funds from their accounts in either currency from what I was told.
This May or may not still be a viable option. PNC Bank bought out the US devision of RBC in 2012 and renamed the 439 branches as PNC. RBC established a new division in Georgia for their Canadian customers. PNC reportedly paid roughly $3.5 billion for the US assets of RBC.