Musicians Friend will ship to Canada. I have had good and bad experiences with them.
The shipping might be a killer on an amp though, so watch carefully.
The bad experience was with a sax mouthpiece. They shipped me the wrong mouthpiece

Since I had already paid customs on it, they said to ship it back saying I didn't want the customs reimpursed and they would ship the correct mouthpiece.
Well, they where out of stock and no longer stocking the product
They reimburssed me for the mouthpiece and all shipping costs. But I was out the $30 for customs.
So the moral is to always ask to be reimbursed for the customs if you are returning an item, even if they are going to send you one back.