Very interested. I live in an early 19th century cape. It's been said that the greenest home is the one already built. Older homes can be modified to have better energy efficiency, while keeping all that old growth lumber out of the landfill.
I'm a REALTOR and most of the people that I know of that are interested in going "green" are a little discouraged because of the local town zoning ordinances and the fact that quite a few cities and towns don't allow windmills. Of course not everyone wants a windmill but the few people that I know who are interested in "green" houses happen to be interested in windmills. The solar panels don't seem to be an issue. The additional cost for some of the "green" materials seems to be a factor too.
I am a realtor who lives in Westport. Most green home buyers I have come across retrofit the home after purchase. I have a client with a windmill and two large outbuildings with solar panels. I have yet to encounter a buyer with a specific request for a green home.