I had the great pleasure to speak with David Geary of Geary's Brewing in Portland, Maine for about a half hour yesterday. Geary's brews two beers that I would call American classics--their Pale and London Porter. Both are brewed on a traditional Yorkshire system: open-fermented in "Yorkshire rounds" with a yeast originally from the Ringwood Brewery in Hampshire, England. (Geary's brews a beer called Hampshire Special Ale that has nothing to do with a neighboring state.) The yeast has been through so many generations that it is probably now more Mainer than English. It certainly behaves differently than the yeast at Gritty McDuff's and Shipyard, which started with the same strain.
This video doesn't capture quite the depth of our conversation, but it gives you a flavor. If you're ever on the East Coast, try to track down a bottle.