Robot barber
I picture something that fits over a person's head and uses some means (static electricity?) to separate the 100000 or so strands of hair on a person's head and catalog each of them in a custom database for that individual. The hairs would also be analyzed for color, split ends, oiliness or dryness, and type of curl, so that all of this information could be combined to present the user with a palette of possible choices for their hairstyle
When the selection is made, a vast number of nanobots would go to work on the person's hair, clipping, coloring (or bleaching), crimping (or straightening), and application of product, while a gentle airflow carries away the clipped ends and the spent chemicals. If you had a number of bots comparable to the number of hairs, it should only take a couple of minutes before the final result might be ready for styling into a unified hairdo. All the bots would be suctioned away, or maybe a few thousand maintenance units might be left in to keep things in order after the visit.
Or it could be the kind with the silver arms and a straight razor like this one, I don't know. It all depends on what one would willing to pay for the tech. Given the right programming, I think one could achieve results that would make today's extreme hairstyles look tame.
Update: It seems to have been devised independently, static included, sadly sans nanobots.