Dumb question here...What if you partially froze the meat before cold smoking? Like half and hour to an hour, depending on size and thickness of meat. just sayin. Pam .☆´¯`•.¸¸. ི♥ྀ.
I would think, that anything that helps to keep the surface temperature of whole cuts of meat below 43° has got to help reduce the risk. How well smoke will stick to a partially frozen piece of meat, I can't say.
Also keep in mind that freezing will NOT destroy C. Botulinum spores; they simply remain dormant until the right temperature & conditions are met. So even if frozen, I'd still limit cold-smoking to around 30 minutes or so, just to err on the side of safety, and I'd still sear it off before serving.