I'm not sure any of them have a set time table for decision, with maybe the exception of Butler now if he really does decide this week. I just know that all 4 are supposedly really close, so it could be tomorrow, it could be a coule of weeks, or God forbid it might fall apart and might not happen at all. I don't think that's very likely though. For intance Newman was going to commit this weekend but then decided not to, because he wants to make sure he is 100% sure, McCarthy told Dayne Crist that if he commited to ND then he would be able to call him a teamate, because he would probably be follwing very soon, Butler's dad wants him to go to ND and he has said that ND will "Definitely" be one of his final schools, at this point it looks like it's going to be a USC v. ND battle, and then there's Slaughter, who' parents now want him to come to ND, he has said he doesn't mind the cold and he would get used to it, he made good friends with T.Smith, and M.Richardson, and it now looks like he wants to leave the state for college and ND's main competion is UGA, and GT.
You always have to remember though that they are just comming off of a great and really fun visit, and a high schools kid's mind can change multiple times in the span of a day, let alone a couple of weeks.