Looks like they only sell it at Mt. Vernon, so not even a specialty whiskey shop may be able to get it. At least, not yet. These "craft" distilleries are popping up all over the place - they often start out covering costs by selling newly-made or young whiskies while aging more for a broader release.
in the meantime, look for some Templeton Rye. That's some nice stuff. Same with the pricier Sazerac 18.