Just wanted to make the point that different theatre zones (Regions? markets? whatevs) have different tastes. The difference between (for example) Chicago acting and New York acting is frequently remarked upon. But I've noticed that what is considered good acting in DC is different in noticeable ways from what is considered good acting in New York. There's a certain archness (and/or deadpanness) in a lot of New York acting that many people I know in DC find really distasteful. I was talking to a director in another city who said that actors in his neck of the woods had a certain distaste for technique-- good acting there had to do with rawness and possibility, rather than a more finely tuned performance.
As the Regional Theatre Movement gets older and older, this will become more true, rather than less. And I think as this happens, the out-of-town-casting paradigm (or "migrant worker" paradigm) will become less and less tenable. If what is "good" in even a town as close as DC (or Philadelphia for that matter) is different than what is "good" in New York, then the search for an actor in New York becomes, essentially, a search for someone who is out of place within their own scene. This may, in fact, be happening already.
UPDATE: Matt Freeman mentions Seattle as well. Which reminded me that a lot of theatre artists I really like (and who have gotten a lot of good ink over the past few years) here in New York not only are all from Seattle, but they all worked with or were part of a company together called Printer's Devil (if memory serves).