Be aware that almost all banks are repossesing overvalued properties.
Their book value (usually almost the same as the amount originally lent) is higher than the current market price, because of the subprime mess.
So it depends completely on bank internal policies.
If they are aware that the market is nowhere near a bottom, they may accept a much lower offer.
If they prefer "book profits", they may keep the house until some (idiot) will pay the ridiculously overvalued book value. It may make take years, until they finally decide to auction it and accept any low price.
So, in short, make an offer much lower than the market value. Providing a clear, WRITTEN explanation of WHY you offer such a low price, may get the deal done.
You may even prepare a nice price analysis/projections of properties on your area, perhaps even with some technical analysis of property prices.
They need to justify why they sold below book value, "causing" losses.
Of course the loss was realized when they lent the mortgage, not when they sold, but well, that is how banks operate.
Be prepared to negotiate.
I know all this because I did it.
Feel free to PM me if you have questions.