I'm from KY, and my '91 318iS may be up for sale in a year or two. xD
I don't know where to look either. A friend of mine owns a shop, and one of his customers was selling my car. Unfortunately, my car came from New Hampshire, and the guy I actually bought it from didn't have it very long.
If you know anybody that works on lots of BMWs, ask if any of their customers are selling one. I've never seen another E30 318iS here in Lexington.
Good luck!