Not bike frame's but i have posted large kit car parts to Canada, I used parcel2go, at the time it was £37 for up to 10kgs, but now i see it's down to £17 for up to 70kgs!
The only "point" to watch for was the filling out of a customs form, they missed that bit, but Fed-Ex (the couriers dealing with the shipping) were on the ball and sorted it all out.