That's something that I wanted to do, but I found that at the scale required to make a unit relatively easy to 3D print (so that as many people could make on as possible) I did not have the space. As the head gets heavier you require more magnetism to hold it in place. As the magnets get stronger you need better rollers or ball bearings to allow it move over the ball with little resistance. What's offered here is the sweet spot I settled on between features, cost and skill requirements.
Go for it though, it's certainly possible! Share a video if you get it working.