I don't know of any designated bar in Stafford or Fredericksburg for Alabama football like ODB, but I always met other Bama fans in places I go watch the games. I've met several at Glory Days in Woodbridge.
Might want to try Mick's in Stafford off of Rt 1 near Aquia Harbor....its a huge Steeler's bar on Sunday's but a decent mix of fans for college games. I've haven't been to Fredvegas in a while, so I wouldn't know where to point as far as a place there.