Yes banks will consider paying some or all of your closing costs if they are reasonable and customary for your area. You can write up any amount you like in your offer but don't go into an offer expecting (or needing) more than 3%. And be financially qualified and prepared for a counter-offer on property price to within a reasonable range of current market value. Unless there are condition issues most banks are not accepting lowball offers. So if you take yourself off the market to wait for a short sale for 90 - 120 days you want to make sure you have an acceptable offer on the table with room for negotiation.
Since closing costs are so ridiculously expensive here in the NY Metro area, a "Seller's Concession" to pay a Purchaser's closing costs is often a necessary part of the Offer and Contract to Purchase a home.
The most I have seen allowed as a Seller's concession for closing costs on a Short Sale is 3%. This concession must be included in your initial offer and contract of sale (or Purchase Memo) and must be disclosed to the Short Sale Lender from the outset. The concession becomes part of the Short Sale Lender's deliberations on the Short Sale approval. I have seen some Short Sale Lenders approve a Short Sale but without a Seller's concession, even though the concession was disclosed from the beginning. In many cases, this may be a deal-killer because a Purchaser may not be able to complete the transaction without the assistance in paying closing costs.
A lot depends on who is handling the short sale negotations on behalf of the Homeowner.
But you still have to get that total under the Appraisal.
Good luck and may God bless