I recommend to my clients to keep looking at homes while they are waiting on bank acceptance since one does not know what the banks answer will be and how long it will take. In a market with mortgage rates that are bouncing around, you could find a home that you like as much if not more that you can purchase. With the uncertainties that a short sale provides it makes it hard to lock in a rate because you do not know if and when you will close.
Keep in mind that deals can be a foreclosure, a short sale, or a normal listing. Do not limit yourself to short sale properties. They are properties that are selling for market value... the reason they are called short sales is because market value is less than what is owed. If they could sell the home for what is owed then it would not be listed as a possible short sale
Best of Luck and Happy House Hunting!