For the canadians

[Wompet]

I'm not lurking, I'm a member! Sheesh!
As someone who deals with this sort of thing (and the UPS and FedEx customs brokers) daily, I second everything Steve said above.

• Get the NAFTA Certificate of Origin
• Ship by US Postal Service/Canada Post. It will take longer, but the broker/carrier won't be charging you an exorbitant fee. Also, if Canadian Customs is like our International Mail Branch, they're not going to be worried about a package of clothes. There are too many packages and too little time to tax clothes when there are higher ticket items to find.
• Post your kiltmaker's name. Maybe one of your fellow Canadians has dealt with him before, and could give you feedback from personal experience.

And one last word on FedEx - .
Sorry, I needed to get that out of my system - they've been again.

I almost forgot - NAFTA will apply only if you're using a US kiltmaker (obviously).
In the case where NAFTA doesn't apply, you can find which applicable tariff will have you pay the least, and have the kiltmaker put that tariff on the invoice. I have a link for the US Harmonized Tariff Schedule around here somewhere; I've never looked for the Canadian version but I'm sure it can be found ...