It would be easy to generate a cad design and print it. Test it and if it does what you want, you can have it printed in metal.
or keyed to the transmission so they move with the transmission.That's a good point. I have felt it move but never paid attention to just how far. Initially I would say it doesn't move THAT much but without quantifying it, well, you'd have to find out how far in order to allow for it.