Arkane Studios revealed that three DLC packs for Dishonored are in the works, the first one call Dunwall City Trials coming out in December. It will be $5 and have 10 challenge maps that will test the different aspects of the gameplay (like one will be a hoard like mode). There also will be a online leaderboard for these challenges.
The other two DLC are story driven with the second DLC pack (coming spring 2013) involving Draud and his group of assassins, and that the choices made in that DLC will affect the ending to the game.
Sounds good. Love Dishonored so I will definitely look into these.