Guys,
Here in Australia we still have loads of sand green courses. Being a dry continent, small towns play only from February-March to October-November, due to heat and lack of water. Typically, a town with such a course expects to one day be able to convert to grass greens, if population and funds materialize. They are born of necessity, not desire.
The greens in my experience are always absolutely flat, at ground level, small and circular.
The courses are never great, obviously because they are usually volunteer run and maintained by a tiny band of loyal locals. I remember fondly heading out to some of these tracks in my junior days. Perhaps my fellow Aussies could volunteer a nomination for most interesting sand green course? Given their usual domain is flat, semi arid farmland, a pleasant deviation from this norm could hold some charm.