xbox there is definitely no harm in sending them an unsolicited request to purchase. I know people who have literally knocked on doors. I left a note for someone in scripps a year ago when I was looking. Many times the sellers are actually trying to do a loan mod either by themselves or using an attorney. If there is a NOD on it then yes any realtor can help you find the basic information. If you really want to arm yourself with alot more, go downtown and pull up all the records at the county recorders. There may be other liens, IRS and otherwise that will be useful for you to know about.
Personally I have never heard of a homeowner and a buyer working out a short sale with the lender in a FSBO type of manner. It may indeed be possible, you never know unless you try it. The first hurdle though is approaching the homeowner to see if they will entertain the idea.
Denial runs in many directions and many homeowners in deep trouble with lenders tend to deny the situation. Even when valid unsolicited offers come along they blow them off with some delusional attitude like they will be able to keep the home and everything will be alright.