I just saw Eclipse, and it seems like it could be turned into a magnificently terrible D&D 4e campaign.
It’s a high-powered paragon level campaign. In addition to their regular powers, everyone gets to choose a few cool powers from the Monster Manual. However, every adventure is concerned with protecting a level-1 NPC minion.
The NPC, Bella Swan, a) has an annoying personality and b) always acts in the most suicidal way possible. Bella Swan has no standard actions. She can, however, Mark as a minor action. In combat, Bella’s usual strategy is to move adjacent to the most powerful enemy and then Mark two opponents.
Besides fighting their opponents, the PCs must nursemaid Bella: use forced-movement powers to get her out of danger; mark opponents to override her marks; Grab her and drag her out of danger; hide her in a box or a cave, with at least one PC assigned to keep her out of trouble. Oh: concealment doesn’t work very well, though, because all the DM’s monsters always know exactly what square she is in because of her unmistakeable smell. They will also attack her instead of any other opponent.
Actually, maybe Bella’s not strictly a minion. She has 2 HP. When left unattended, she’s always getting Bloodied by, say, cutting herself on a sharp knife. If this happens, the party cleric had better immediately use healing resources on her, because there are more sharp knives lying around the world. (Let’s give Bella another ability: whenever she becomes Bloodied, she immediately Marks all opponents and allies within 5 miles.)
If any PC kills Bella, he immediately gains a level. However, the campaign ends.