DON'T DO IT. If you can't afford a modification, or you can't afford to save your house in bankruptcy, then live there as long as legally possible exercising all of your civil and bankruptcy rights. I have one client who has stayed in his house for 18 months no mortgage, no rent. This is only one example and does not constitute a promise or guarantee that you could have the same result. But why make those real estate brokers richer with short sale commissions and you lose again. Don't do it.
The Kudlow report is insane! check it out!