Also check out http://www.masterchem.com/index_hammerite.html, I have heard if you ask them they can tell you who in your area has bought any recently. I also get it locally at True value Hardware and the aforementioned (thanks Chris) Hamilton Marine.
Winter Harbor, Maine
'81 CJ-8 Scrambled!
It's a Jeep, Chevy, IHC kinda thing!