Halsey-UK has done most of my work including the bolt rope on my 6.0. They are located in Mystic, CT their website is www.ukhalsey.com
Other sail makers i'd reccomend but haven't had much experience with are Farrar sails in New London, CT or North Sails in Portsmouth, RI.
Not sure about anywhere in Northern New England though, i'd reccomend staying with lofts that have experience in catamarans or at least modern one designs.