Fyi, don't know if you've seen this before, but while the 35mm Schwalbe Marathon Winter used to be the skinniest decent studded tire (there was the Nokian A10 to but reports weren't great on it), 45nrth now makes what sounds like a good 30c studded tire:
45NRTH Xerces Studded Tire





I mention it in case it might happen to fit your current drop bar bike, or it might make it a bit easier to find a used bike that it would fit on. I know a 30c tire, for example, just fits onto my older Specialized Seqouia (I know because they put one on, I didn't like the tire they choose so they took it off) - and this was one of the models where there's not really clearance for wider tires, fenders, etc.