All private schools accept Canadians (at least the ones on the east coast). I applied to a bunch all over the northeast. The only thing you should look into is the pre-requiste courses b/c they are usually different than for schools in Canada. I know there are a lot of Canadians in BU, probably Tufts and Penn as well.
If you have really good stats you can apply to state schools as well, but they are harder to get into since they only take a certain percentage of out of state students.