Is the issue that Burpee and other US sellers can't/won't ship to Canada? This seller on eBay has a Porterhouse listing and says they'll ship worldwide:
https://www.ebay.com/itm/114645456585#shpCntId
Or maybe you could do a new post in the "Wanted" section, with Porterhouse in the title. Your post might be kind of lost here in this thread.