Found on Samizdata's Glossary:

Tranzi
noun. Derived from 'Transnational Progressive', a term popularised by John Fonte. Transnational Socialists. Not a term of endearment.

Bah. The proper word is TransProg, which summons up juuust about enough contempt for the entire concept to suit those of us who didn't self-interestedly buy into the concept of TransProg as a way of categorizing that which irks wingers.

(Interesting, though, that the new TransSoc variation shows people already slowly moving back to the pathetically obvious source of TransProg: the oft-demonized International Communism.)