As someone thinking about a natural-eared puppy for my next dobie, after rescuing my natural-eared first dobie, and who is willing to drive long-distances, is there a good way to find out which Canadian breeders would leave ears intact and do the requisite health testing to produce sound dogs? Not looking to make any moves immediately, but perhaps in the next two years or so.
Best thing to do is ask. Even those that prefer to let all their dogs go to homes cropped and docked will politely decline rather than be offended by the question. There isn't really a list of breeders who specifically allow natural eared dobes. You're better off asking about health testing first and then asking about the ears.
I'm not real familiar with the Canadian breeders out on the West Coast, the only ones I know of are Supernova Dobermans and Holmrun in BC. Supernova don't breed often but they produce really nice dogs. I do think they health test but I can't vouch for that as I haven't seriously looked into it. Not sure if they let any of their puppies go home uncropped. Additionally Danica and Catherine Eisworth (daughter and mother) are incredibly nice and welcoming people. Met them a few years ago at the DPCC nationals. They recently co-bred a litter with Denmel in Alberta.
Here's the DPCC breeder directory, might be a good place to start. https://dpcc.ca/xbreeder-directory/