Abrams not doing Star Trek sequel right away?

Even though there has been much murmur going about on how soon J.J. Abrams will be putting together the sequel to his Star Trek movie, it might be later rather than sooner. JoBlo reports that there might be another film on the horizon for Abrams, but not one that we all know of. The ones that we do know of, other than the sequel to the Chris Pine starring Star Trek, is the development of Mission: Impossible 4. The New York Times lets slip out that there is a tent pole movie that the director has not yet revealed to the general public but is currently working on it.

What exactly could this be? It could be a great array of things, but this is the part once again where I ask you guys what the newest project could be to sidetrack him away from a Star Trek or Mission: Impossible sequel?