Automatically adjusting bed

One of the problems of crafted beds and pillows is that they only work if the sleeper sleeps in the same position. A possible solution to this would be beds that automatically adjusted themselves to move the sleeper into an optimal position (e.g. for spine alignment). The sleeper's position would be detected from pressure sensors, and perhaps 3D scanners (e.g. Kinect). Under the mattress (which would need to be a flexible foam mattress) would be a bed of hydraulic cylinders (or equivalent) that could raise an lower a particular area of the bed (a greater number of smaller cylinders gives finer control over the areas of the bed that can be raised and lowered). Obviously, the cylinders would need to move slowly and quietly so as not to wake the sleeper.