basically, what bill said.
sanctuary bonsai & new england bonsai used to both feature nick's pots in their online catalogues, but it's been some time since i've seen any posted. that said, you might want to contact those vendors directly in case they have one collecting dust under a work bench or on a back shelf.
http://sanctuarybonsai.com/
http://www.nebonsai.com/mm5/merchant.mvc
considering the quality and the cachet of NL's ceramics, i was always in disbelief over how ridiculously cheap they were priced --- but, i suppose, long quiet winters allowed him to produce in something approaching volume.
that appears to have changed, however, as less containers (if any?) are being made and more enthusiasts want a little piece of nick's 'mo-jo' for their own.
I don't know nick personally, but he may yet have a shed or barn full of pots on his property. i doubt you or anyone could convince him to put one in the mail, but if you're close enough to visit (come spring) he'd probably sell you one.
otherwise. hang in there. keep an eye on the various NE nurseries, eBay and/or the 'bonsai classifieds' page on facebook. AND there may yet be a more materially helpful response to your post here.