For those of you in Canada... I asked Mr. FedEx about duty to Canada, and according to their tax/duty estimating tool, there is no duty to Canada - and it doesn't matter whether the country of origin of the fabric is US or whether it was made in China, S. Korea, Indonesia or Japan. Meaning, it's not because of NAFTA that there's no duty. It's that Canada doesn't charge duty on inbound cotton quilting fabrics. Mr. FedEx thinks that is because Canada didn't historically have a textile industry. I suppose that makes sense, because "textile industry" is nearly synonymous with "cotton" and we all know that cotton is a southern crop, not grown in Canada.
HST would still be due, though.