> software to fly the drone into the person... and thats probably around somewhere out there as well.

ardupilot + waypoint nav would do it for fixed locations. The camera identifies a target, gets the gps cooridnates and sets a waypoint. I would be shocked if there wasn't extensions available (maybe not officially) for flying to a "moving location". I'm in the high power rocketry hobby and the knowledge to add control surfaces and processing to autonomously fly a rocket to a location is plenty available. No one does it because it's a bad look for a hobby that already raises eyebrows.