This would be a label that I would attach to a new generation of Catholics and other Christians whose adherence to theological and church tradition runs deep, but not in any way that is reactionary. And typically, I notice that to see open traditionalism in action, you have to look in areas of the world where there are not culture wars raging to such an extent that traditionalists get caught up in the heat of cross fire. That is: don't look for it in the United States where traditionalism is so often associated with political neo-liberalism or crude apologetics or some sort of ideological substitute for a more genuine (read: charitable) expression of Christian faith.
Today's New York Times has an article about the Dominicans in Ireland, whose expression of faith strikes me as a form of open traditionalism. I say this not only on the basis of the article however. I make this observation also with the benefit of having spent a few months of a 2010 sabbatical at Blackfriars, a private academic hall at the University of Oxford that is run by the English Dominicans. In fact, I had heard about the Dominicans' successes in Ireland (and the UK) whilst in Oxford. The NYT article focuses a bit much on the habit to my mind - a typical secular journalistic fault perhaps. But the genius of the Dominicans is - as I saw it first hand - to blend the life of prayer with the academic vocation and the personalist, pastoral vision that is best experienced in the preaching of the friars who live in the priory and who minister in local churches, such as the Priory church on St. Giles St. in Oxford.
One more note: it is thanks to the Dominicans that we have a good news story about Catholics on the pages of the New York Times. No small feat.