Hmm... I'm kinda stumped then, but my gut tells me that aside from the characteristic blue cloak (yeah, I know it's the obvious clue in that direction, but...) and the chain link belt (which is hard to see, and I don't what to make of) he doesn't seem very Gallic. All of his equipment is within the traditional range of Greco-Hellenistic-Roman military equipment, which would only make sense on a Gaul either in Massilia or another Greek colony (though the phrygian helmet would seem rather odd at that point) or as a Galatian mercanary in Egypt or Syria (but only at a later date than the painting and far away from Etruria). Also, the way he wears his cloak reminds me of the Royal pages of Alexander's court (or just the way that Hellens in general wore their cloaks). I don't claim to be an expert so... I don't know. You definitively know more about the galatians in Greek lands, so in that sense the blue cloak would point straight to a Celtic origin, but my gut feeling still says native Etruscan. Maybe someone else with a better knowledge of ancient Italy can help.

Chairman