Clotilde's carries it--- and Nancy's notions...
i've been shopping on line for 10 years---what are you afraid of??? i've never had a bad experience because of it being an on line transaction....and with the whole world at your fingertips it sure makes it easier to find the things you need.
clotilde's is the only place i have found it- but most art supply stores should have it or be able to order it for you- since it is used for all kinds of archival storage.