MP, yes, Short sales are particular to the sellers and the bank(s) involved. I have a real estate blog post that might help you. See below.
The trick with trying to time a short sale is that you must be ready to close whenever you get the word. That could be in a week, that could be next year. The "norm" is 6 - 8 weeks for approval, 3-4 weeks for close from that point. IF you decide to write on a short sale, make sure that the listing agent knows what they are doing - this is critical, and make sure that they will be ratifying a contract before submitting to the bank. Don't play with the ones that are collecting offers and sending them to the bank for approval unratified... you could be waiting in a pool of a dozen offers or more for months, and that is simply unfair.
Be sure, whatever you do, to have a buyers agent working FOR YOU, and make sure that agent knows there way around your market. If you're not working with someone already, I'd be pleased to talk with you about this process in detail. firstname.lastname@example.org 703-669-3142