A mattress called SAT (Self Adjusting Technology) mattress or SAM (Self Adjusting Mattress) is sold by a company called Comfort Direct. They have a page of 'testimonials', but I have been told by one of the people quoted there that she was wildly misquoted, and the picture shown was not her.
There is more about this mattress on the epinions website, including this comment:
"Avoid Comfort Direct at all cost! SAM may be an O.K. product, but Comfort Direct is the worst dealer I have ever dealt with. Returning the SAM was my worst and longest experience. No one but Kevin can talk to you about returns or exchanges, and Kevin will make your worst nightmare come true. He will make you hold for hours or tell you to call him back in 5 minutes every time you call him or flat out tell you that he will not honor any of his guarantees. Don't believe their "90-day home trial" guarantee, 60-day money back guarantee or 20-year manufacturer's warranty. Worst of all, if he wants something from you, he will call you day and night, literally."
Updated 2005-07-17