Trust me, what I'm after is well rooted on the C&V side of the house. I don't mind modernizing a tad but I want to keep my bike grounded on its vintage heritage. Were I to ask in a mountain bike forum most would not even comprehend the concept of trying to stay with 80's tech.

So far the best route seems to be a Suntour AG (which by itself can chew on a 38t cog) with a hanger extender, paired with a Specialites TA crank sporting a single speed 44t ring. That would give me a gear-inches range from 103 to 27. I would go smaller on the crank but finding sub 44t rings for the outside 5-bolt position on the TA crank is not trivial.