I would pay a surprising amount of money for that kind of interview. I interview quite a lot, having my ear to the rails pretty much all the time, and to keep my interview skills up to par. I interview perhaps once or twice every couple of months, or less if I don't have the spare time, since it is expensive to do this much interviewing. I have yet to interview at any tech company -- literally any tech company -- that has made good on their promise to tell me why I was rejected when it happens. Not a single one that has ever rejected me has ever gotten back to me. I should say that I'm rejected probably a couple of times a year. It happens more regularly than you would think. I should say that I don't mean I want to pay one of those interview boot camps. I want the kind of interview you've just described.