The Dogfish Alehouse at 7Corners and Fairfax is now selling growlers. They will refill any growlers as well
The one in Gaithersburg didn't about three months ago. Pissed me off.
On another note, here is a pic of a Baltic Porter I brewed in January 2011. Had the final pints of it just this past Monday. With out a doubt the best beer I have brewed to date.