Spacetec IMC, formerly Spaceball, made a name for itself with extremely versatile controllers for CAD, or computer assisted drafting programs.  This same basic interface is now available for game players with the Galaxys SpacePlayer.  The ball does not actually move, but is extremely sensitive to direction and degree of touch, so this is not just another track ball.  SpacePlayer provides full 3D control without having to think about axis shift.