Good kite shops ? Uh, no. Wait, there is a place in Sag Harbor, or was, right on Main St. I actually bought my first stunt kite there. There was a store in Southampton, don't know if it's there anymore. There's actually a Prism dealer in Port Jefferson, but their kite inventory was pretty sad the last time I was in there.
Your best bet is our host, http://www.chicokites.com/store/
If you don't see it listed, contact Steve, he probably has what you're looking for.
As far as getting together for a fly, weekends are best, I work M-F 9-5. It would be good to see another flier on the beach.