I've thought about this circumstance (because I'm in it). Here's my conclusion. The answer lies in where the programs are in their interview schedule. In other words, if the programs have handed out all of their interviews, you're up the creek even if you apply to 500 new programs. I tend to think that most programs hand out interviews to their "first-tier applicants" before the Dean's Letter even goes out. Yes, yes, I know they say that places don't make up their minds until after Nov. 1, but we all know lots of people who got interviews before the Dean's Letter. After that ruckus has cooled off, the Dean's Letter goes out and they give out their "second-tier interviews" to a bunch of other people. At that point, a lot of people will have to turn down at least SOME interviews and they fill in the rest with their "third-tier interviews." I think they are in this last group right about now. I doubt that applying to a lot of places at this point would change anything.