I bought my Moulton ATB from Angle Lake Cyclery in 1989 via phone order and was pleased with how they handled things.
Gilbert Andersen of North Road Bicycles in North Carolina is also a great guy to deal with about Moultons. He has a good stock of bikes and rides them on tour in Europe often. Give him a call at 1-800-321-5511. [That is the Eastern US time zone.]