I have seen it but have not been impressed with it. Years ago I used a tracking system for show productions that was setup so the lights would track the artist on the stage as they moved.
All the soloshot does is have two GPS units. one in the base and one in the tag. You calibrate so they both match up and then the unit computes your location based on the GPS comparison of where the tag is and the base is and moves the head to follow that.
I am much more interested in a unit that can have a moving tag and a moving base. I want a octocopter that can auto track and film me as I move.