do you want the motion or the sound to help you sleep.

I don't know if they built it, but there is already a patent on such a device: "The present invention concerns an oscillating bed supporting structure. It is particularly adapted to provide conditions for a snore-free sleep, but it is believed that it would serve as well as a remedy for other insomnia problems of adults as well as it would serve to rock babies to sleep. It is also likely that it would reduce the risk of bedsores. The invention is based on observations that people normally disposed to heavy snoring do not snore, or, stop snoring, when sleeping in a moving train. These observations include the observation that - in some instances - snoring is resumed when a train stops, and ceases when the train starts moving again. DE 38 36292 describes a "Bed for snorers". According to the Abstract of the patent, a superficial mattress support, which can be pivoted about a longitudinal axis from the horizontal into an inclined position by a controllable drive, rolls a snoring sleeper automatically into the lateral position without waking him, so that he stops snoring. Since the bed can be pivoted back into the horizontal after a short time, undisturbed and relaxed sleep is said to be guaranteed for the snorer." Source and further information: http://www.wipo.int/pctdb/en/wo.jsp?wo=2006135320&IA=WO2006135320&DISPLAY=DESC