I'm not sure how Canadian sellers are coping with dropshipping products from the US since based on what I have read Canadian Customs will collect GST on most anything that's been imported into Canada, usually a 5% tax is charged depending on the converted value.
Here's a blog post with an issue quite similar to yours, I think you'll find it and the comments quite useful -
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One more thing, since there seems to be no legal way around this it might be best that you mention in your listing that the product is coming in from the US so that your customers are aware of the additional fees.
I found a Canadian dropshipper that may have products which you can use - Link hidden: Login to view
Hope this helps :)