First of all, there is closing cost for both seller and buyer. I assume your question is about buyer's closing cost.
Closing cost is negotiable. As a local agent in San Gabriel Valley, in most cases buyers pay for it in order to get the best deal possible. However, you can definitely request the seller ( in short sale, bank) to pay for it. I had several short sale/ bank own deals that I successfully negotiated with the bank and helped the buyers to get most or all closing cost covered. Pls note, there is recurring ( prepaid interest, property tax and etc) and non-recurring closing cost ( escrow, lender, title fee and etc.). Some banks will only pay non-recurring closing cost. And usually it's up to 3% of the sales price and also depends on if the property is for owner occupied or investment.
Hopefully the answer helps. Feel free to let me know if anything else I can help.
Go Go Realtors
With Short Sales it would be not that easy: The Short Sale lender will not cover ANY closing costs on behalf of the Buyer. The bank's position is that they are going to take a hit on the Short Sale, they loose money and they pay for defaulted homeowner closing costs( and often the cost of a home warranty if requested by the Buyer, HOA transfer fees and certificates, and delinquent HOA dues; add a Seller Incentive for relocation, etc.)