Gipiemme still exists, but they have poor distribution in the USA.
http://www.gipiemme.com/JJ_SITE/JJ_MAIN/JJ_ShopCase.asp

Nemesis outdoor is the UK importer, and there is a German importer too. A bunch of guys on the Weight Weenies forums got together a while back to order some of the rims.

I also strongly suspect that the Dodici rims are actually the Gipiemme rims, or at least are made by the same people (maybe DRC Cerchi). The Dodici rims would be easier to get.