Hi there, Laddie. I know this may sound very bold, but seeing as there is no land publicly being sold in that particular area, you could find out for yourself who owns what and contact them personally.
There is an old saying that everything is for sale, for the right price.
You can certainly check out http://hudsonnh.patriotproperties.com/default.asp and find which address it is you like, contact the owner directly. They may have no idea that someone would be interested in purchasing a small amount of their land. They may say no and hang up. You really just never know, until you find out!
That is a very nice part of town, good luck to you!