Jack Campin: There are many folk music 'camps' held in Transylvania over the summers, in many other places than Gyimes and Moldavia.
The link "nyari taborok 2008-ban" on this page lists them (in Hungarian only at present, they usually post an english version eventually).

Open mike: what you heard about the 'taraf de haidouks' band is absolutely correct. The core of the group were originally the local musicians from the village of Clejani. Nowadays they bulk out the lineup with musicians from Bucharest (not far away, and a much bigger pool to draw from). Although I think it's funny they keep pushing the 'Authentic Village Musicians' angle in their promotion, in many ways what they're doing does not go against the tradition, as there has always been a strong musical interplay between Bucharest and it's satellite villages, and in any case the idea of a fixed 'band' with always exactly the same members does not have a great deal of currency among lautari.