I just found two us/canada saves at this website:
Wii Save - Nintendo Wii Game Saves > Mario Kart Wii
I tried the second one that says "AMERICAN ACTION REPLAY CHEAT" and that one has NO friend code locked in!!! The only thing wrong with that one is that "mii outfit B" is NOT ulnocked (but who really cares about a second mii). I HAVE NOT tried the one at the top of the list though, so sorry, I don't have a review on that one.
So unless you really give a crap about "mii outfit B", I recommend the action replay save on that website.