I'm now seeing confirmation of this story, so I won't call it a rumor. Entertainment Weekly is reporting that Tim Burton will direct the film adaptation of Abraham Lincoln: Vampire Hunter by Seth Grahame-Smith. Here is a plot summary:
While Abraham Lincoln is widely lauded for saving a Union and freeing millions of slaves, his valiant fight against the forces of the undead has remained in the shadows for hundreds of years. That is, until Seth Grahame-Smith stumbled upon The Secret Journal of Abraham Lincoln, and became the first living person to lay eyes on it in more than 140 years.
Using the journal as his guide and writing in the grand biographical style of Doris Kearns Goodwin and David McCullough, Seth has reconstructed the true life story of our greatest president for the first time-all while revealing the hidden history behind the Civil War and uncovering the role vampires played in the birth, growth, and near-death of our nation.