Well, now we know. It's a project called Pay The Ghost for Sidney Kimmel Entertainment, a production outfit not exactly known for its genre fare. But that's okay, because the plot sounds fantastic. From Variety: "Story kicks off on Halloween night, when a couple's young son is mysteriously abducted. A year later, they begin to sense his presence in frightening ways. A string of terrifying clues draws them to search for the boy throughout New York, where they uncover ancient secrets and discover a vicious, vengeful spirit."
If that sounds familiar, you may have read Tim Lebbon's short story of the same name it's based on. Dan Kay will be taking on the adapting duties, which sounds good to me since Kay's most recent film contribution was the well-written, good-but-not-great backwoods killers film Timber Falls. No cast has been attached yet, but hopefully it won't be too long before we find out who will be haunted on Halloween.