I've contacted sellers directly on behalf of my clients. It works occasionally.
Was sold in 2002 for $414k. Loans on it before it foreclosed was $424k and $90k. Chase bought it back (on paper) for $329k in May 2010. Comps have it close to $400k.
It's not on the market yet. They've got to get hold of their REO agent. It can be weeks, sometimes months.
I always recommend you work with an agent...after all, it's no cost to you and a great help in the process with this complicated market.
Let me know if you need help.