... is not quite this, but it's an interesting proposal:
http://online.wsj.com/article/SB122833771718976731.html
WASHINGTON -- The Treasury Department is considering a plan to revitalize the U.S. home market that would push down mortgage rates for home loans, according to people familiar with the matter.
The plan, which is in the development stage, would temporarily use the clout of mortgage giants Fannie Mae and Freddie Mac to encourage banks to lend at rates as low as 4.5%, more than a full percentage point lower than prevailing rates for a standard 30-year fixed-rate mortgage.
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