Are you prepared to pay considerably more for less (space, bandwidth, services, etc.) web hosting? Because that is what you are doing when you restrict yourself to Canadian web hosts. Economies of scale issues.
Also: .ca domain names confuse Canadians. Say it, print it, advertise, it and they will say still type .com half the time and not find you.
All that said, if you are still interested, I'll ask a friend who "had" to go Canadian because the organization's privacy policies did not permit hosting in the U.S.
One final note: one of my customers already had a well established .ca web site, so I haven't changed it. And I have had zero problems with having the domain name registration somewhere other than my web hosting company. In fact, the Canadian domain registrar has the lowest prices and absolutely the most complete set of automated and well documented manual procedures I've ever seen for managing domain name registrations, bar none.