If you are into a bit of DIY why not make your own. Have seen motors on a certain auction site. Look for linear actuators. I was planning a height adjustable speaker stand that would disapear from view but got too complicated to design without being extremely big. Might work fine for a tv though.
Not my bedroom unfortunately, the wires are managed internally in a caterpillar trucking type thing then go under the bed to the DVD and Sky boxes. Its controlled with a Harmony remote and RF extender. The liftbox has IR control and is just programmed on the Harmony.