I am sorry here but I have to jump in and defend the USPS. Shipping to Canada has been painless and inexpensive with them. They even shipped a flywheel and crankshaft damper (from 440Source) to me by mail. It was so heavy that the Canada Post guy knocked on the door first to see if someone was home before dragging it out of the truck.
Carl - YO is yanking your chain. Anyone can ship via USPS to anywhere. They just don't want to do it because they are most likely not setup to use USPS. I use a YO distributor here in Calgary and they bring the stuff in as a multiple shipment so the costs are down for shipping and clearance. Have you thought about getting hold of someone like these people in Canada, gather your order together (as they are agents for multiple suppliers) then ship one big order in a crate. You should be able to clear it yourself in Wellington if it is a crate size delivery, unless rules have changed. Years ago I cleared my car myself into NZ. The people I deal with here is Muscle Car Shop, Calgary, AB, Canada (403) 569-1957 Brian or Ian