Well, Martin Simpson beats all the others I've heard from the nominations here . . Though I've never heard him play Flamenco, he's certainly covered a vast range of styles in his own playing and in those he's performed with . . (Did anyone SEE the Canadian documentary about the guy on Death Row - in Texas, IIRC - for which Martin did the soundtrack . . which was not quite what he was expecting when he went into the studio?? I've heard Martin tell the tale a couple of times, and gather the programme won an award, but am curious if any of you erudite folks actually saw it . .)
On the other hand, I can also imagine Martin's reaction to ANY attempt to define the "best" or "most versatile" or whatever, so I'll give up at this point . .