So the question becomes, is there a way for real estate investors to enable these folks to stay in their homes but which, from the financial point of view, makes sense to invest?

Here's my idea: investors would purchase the debt on the property in return for an equity interest in it, based on an appraisal of the property. The owner-occupant would remain in the property for the rest of his/her life and the value of that occupancy would be calculated from life expectancy actuarial tables and the FMV of the property rental. For example, assume the homeowner is a male aged 70 living in, say, Contra Costa County(for more than one owner, such as a husband and wife, you might use the age and sex of the youngest person). Using the State of California's life expectancy table, which is broken down by county, that person is expected to live to another nine years. If we assume that the house would rent for between $3300-3500 per month, this would yield a total revenue of, say, $3400 times 9, or $30,600. The present value of this would be $26,772, based on the prevailing US savings bond rate of 2.76%. Thus, in addition to the equity coming from the debt reduction, the investor would also enjoy the equity from the additional $26,772.

To me, this looks like a win-win: the homeowners gets to stay in their homes for life, if they so choose, and the investor gets a fair return on their investment. What do you think? I've never heard of a deal like this, so this could be an untapped market.