There is some vertical movement in the ball, its not completely captured and allowed to slide up and down. There is a plastic bushing that goes in there, don't really see a way around without breaking the rules of trig. The stock mazda shifter moved up and down quite a bit when shifted.
The heim joint/spherical bearing would be easy, but getting 30 degrees in each direction of travel out of heim joints isn't cheap after you factor in having to buy a much larger size bearing and misalignment bushings, and not having to modify the shifter is a bonus. As many off the shelf parts as possible is somewhat of a goal.
edit: If you are talking about orienting the axis of the spherical bearing inline with the shifter rod that might work, I'll have to see if there is enough travel for the up/down shifting (1st to 2nd, 3rd to 4th, 5th to reverse) for an off the shelf bearing, but its possible.