The answer is actually somewhat scary. They are not really equipped with the infrastructure to handle short sales. Now with the loan modification cases added to their melting pot, it is going to get worse. One major lender has put out that they will be doing a loan mod offer to 500,000 homeowners, and the 600 people they will be hiring and training are supposed to handle that workload. 834 individual loans per person to deal with, and no across the board general software that can do each one.
So now throw your short sale and all of the foreclosures into the mix along with many other factors, and you have a long sale. I hope your buyer and seller can hold out. Unfortunately the quickest I have ever saw was 60 days, and that was some good prep prior to starting with the lender. Maybe they are going a little quicker today, haven't done one in 2 years.
If your seller would like to stay in the house, I suggest looking at a loan mod solution, at least as an option in case the short sale falls through. Loan mods can be done anytime for anyone even after a foreclosure sale.
For more info check out our blog. Also you may want to direct some of your clients you cannot help to a Loan Mod. There is a commission for that too.
Hope this helps answer the question.