At least periodically, Canada's NFL franchise could play in Vancouver, in a suitable BC Place, or any other CFL stadium. The TV is where the big bucks are. The seating wouldn't be as big a deal as the ratings of Canadians behind their team.
If it was my vote, I'd be for the next NFL expansion having the Kentucky Downs in Louisville and Canadian Power. The team of all of Canada could be placed in the west or any north-centric division alignment east to west, coast to coast. And CFL could co-exist.