There was a version of this out a few years ago called the "Flowbee". I know becasue a coworker had one he used to cut his own and his kids hair. Man he took a beating for that for a long time at work.
By the way... that co-worker is nearly SLY now. He shaveed it way short months ago and talked to me about the "final step". He hasn't taken that final leap yet though.
