All this sounds very absurd, and it can’t possibly happen.
But in case, I have come up with the only solution that would be fair.
Let the people who bought and sold their house for a profit during this time (1998 until 2006) pay. The ones making a lot of money on this housing bubble should pay, including banks, real estate agents (with their huge commissions etc). There is probably an economic genius somewhere that could come up with a calculation how much they should pay back. Of course the money is already spent, but at least they got a chunk of money to spend, and probably they understand that it is not really fair, and will pay back. Or not!
I feel sorry for a lot of young families caught in this mess, but they will probably never receive a dime from anybody. The ones screaming the loudest will get it, and as all know, those are not the people that deserve it.