Salvete, amici Romani!
I've just been led onto a new-to-me reenactment society in la belle France: "Via Romana", featuring Cohors Prima Aquitanorum. They're a Caesarian Auxiliary outfit with nice equipment and a wide range of presentation-types from the research-oriented to the educational, and of course traditional Gallic-Wars head-bashing. <g>
The site has an extensive history of the Roman Auxiliary force in all its times and places.
Their military arm includes archers, slingers, and many other troop-types you don't normally get to see. They have a civilian side as well, which puts on a varied and very well-staffed vicus or marketplace display. They cook a wider variety of regular-Roman food than I've seen elsewhere, sell things (of course), keep Roman garb to dress the visitors in, and--hei!--they even have a resident beggar, musicians, and a petty magistrate keeping the books!
I couldn't find a reference to when they were founded; but they are a large group, and from the variety of things they do I think they must be very well-established.
Here's their site (in French):
http://www.viaromana.com/
Felices explorationes!