The next Dishonored DLC will very likely be called "The Other Side of the Coin." New trophy information for the game via PS3Trophies gives a few details about what is likely the next pack, which Bethesda last year said will focus on magic-wielding assassin Daud.
It looks like The Other Side of the Coin will resemble Corvo Attano's quest of vengeance, offering trophies for completing the content without alerts or kills, and a similar "chaos" system. We'll be interested to see where and when players will take over Daud's story--if you've played through the main game, you know his regrettable contribution to the story of Dunwall.
Bethesda said it has plans for at least one more story-driven expansion after this one, and that it's "clearly" a new franchise. We've reached out to the publisher for comment on the trophy information and will update this story with any response.