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I do not know of anyone who makes a new one, but a competent gunsmith could sleeve a barrel inside one side of a more modern hammer gun. I would definitely choose an older, lower pressure cartridge, possibly a classic one, and a good quality side x side shotgun.
Baikal makes a double rifle in their production line in 30-06 Springfield, so they must think their actions will handle it. I think they also make it in 45-70 and that would probably be my choice if I was going to sleeve a barrel for a rifle cartridge --- or maybe .43 Mauser because I already shoot it and have fun with it. The 45-70 even loaded with lower pressure Springfield Trapdoor loading should be able to take almost any game animal in Canada that you will come across, be cheap to load, have available brass, and if fitted with a fold down rear sight will give a very nice combination gun.