Can the buyer contact the bank regarding the status of a short sale?

The bank can not legally discuss the sale with you at all, they have to refer you (if you could even get through to anyone who knows) to the agent handling the sale.

Yes you can contact the bank, but not directly, but rather thru the agent who brought the offer to the bank. You can attach a 14 day deadline, but expect that most of these offers will be declined right off the bat, often because the loan was sold and resold to investors long ago. However, you can continue shopping though yourself for other properties. If you find a better deal, you cancel the first deal, because you are not in contract until the bank accepted your offer AND that acceptance was communicated to you.

Unless this house is the steal of the century, I wouldn't sit around waiting for months for an answer. I'd decide what the most you are willing to pay for the house is, and submit another offer to the bank with a DEADLINE of 14 days (if you were dealing with a private sale, your deadline would likely be 3 days or less for refusal, counter, or acceptance). I wouldn't mess around with it, personally-I'd keep on shopping if they won't move faster than that (they are waiting for a better offer to come along from someone else after all this time).

You're wasting your time trying to contact the seller's lender. The more you annoy the lender with persistence, the less apt is the person on the other end to approve your offer. Let the sellers and their agent handle that part of your offer.