To do this in the North American market Capital One would have to modify BMO's franchise agreement. It was evident when BMO bought the franchise from Citi that they were primarily interested in the corporate card opportunity, not in the small business or personal cards. I doubt if it would make sense for Capital One to take back the business/personal side and leave the corporate program with BMO.

It is often easier to launch a new brand than to revive an old one. Capital One could create a premium card running on the Discover/Diners network, with a more generous version of the Venture X rewards program.