The technology is their to make it, but is it reliable for a sport like kitesurfing?. And to the other problem that it would cost a lot of money to make. Nothing like what you described is commercially available yet. If you want aerial video of kitesurfing it would be much better for you to manually fly it via fpv (first person view). To construct it I would guess around $2000+ and a lot of hours of tinkering with it. And just saying that an AR drone is more of a toy. And lastly you would need a few years of experience in multicopters.
This is all is really possible at the moment for following a person. Although it is much easier and more reliable for setting waypoints that the drone follows. A following drone is not really practical.
