I have only seen a setup like your talking about once before. It wasn't a subdivision but a large resort. The Poco metered the 12KV and then set a 12kv/4160 transformer which was then distrubuted to the different areas where they placed transformers for each building.
IMHO based on the size of the subdivision It seems like 480VAC distribution wouldn't quite be enough to power the subdivision without worrying about voltage drop issues or some pretty good sized feeders.
I hope I have been at least a little help
