I watched a program about this last night on BBC news i think it was, apparently the only people to sign up for one so far are Moscow, Dubai are considering it, within every moving level theres wind turbines, which provides all of the buildings energys, its cheap to make and can be made off site and put together on site, minimising building costs and the problems caused by building work going on. Also there is a lift for the wealthy penthouse owners to get there cars from ground floor, say to floor 80 where their penthouse is located!
Sounds interesting, and how the architect was saying it, i think they may be popping up in every city for the value of them, it being eco-friendly etc