This idea, from the indefatigable Peter Morici at the University of Maryland, is promising. Of course, it's largely what the TARP was supposed to do in the first place:

Banks continue to suffer losses on bonds backed by failing mortgages, credit cards and auto loans, and questionable corporate debt. To assist, the Treasury has used TARP funds to purchase capital in healthy and deeply troubled banks alike; however, no one can calibrate how high bank losses will go, because no one knows how far housing prices will drop and how many loans will ultimately fail.

The Obama Treasury could put a floor under bank losses, through government guarantees on their bonds, or by creating an aggregator bank that purchases those securities from banks altogether.

Guarantees would give the banks profits on bonds whose underlying loans are mostly repaid, and shift to taxpayers losses from those bonds whose loans are mostly not repaid. That would require additional large subsidies from taxpayer to the banks.

An aggregator bank, however, could turn a profit. It could purchase all the commercial banks’ potentially questionable securities, at their current mark to market values, with its own common stock and funds provided by the TARP. Then the aggregator bank could balance profits on those securities whose loans pan out against losses on securities whose loans fail.

An aggregator bank could perform triage on mortgages. It could work out those whose homeowners can be saved with some adjustments in their loan balances, interest rates and repayment periods; foreclose on mortgages whose homeowners could not meet payments with reasonably concessions; and leave other loans alone.

Commercial banks acting alone cannot accomplish triage as effectively, because individually they can have little effect on how much housing values will fall. In contrast an aggregator bank, holding so many mortgages and working in cooperation with Fannie Mae and Freddie Mac, could have a salutary impact on housing values. It could put some breaks on falling home prices.