Here is a dead simple solution for foreclosed houses: offer these at cut rate auctions to affordable housing developers like CASCAP in Cambridge, MA. These agencies can use the properties, otherwise fated to decay, for affordable housing for the poor and homeless.
Why we won't embrace this solution:
Few businesses understand the sunk cost fallacy. Banks and mortgage holders cling desperately to assets that continue to decline in value in the vain hope that they'll be worth something close to what they paid.
Remember this: a bag of gold, no matter how valuable, will kill you if you're trying to stay afloat.