This is the gearbox I designed for my upcoming supercar. It shifts gears by lifting and lowering entire gear racks. This minimizes spinning dead gears. Shifting is done using pneumatic cylinders connected to a compressor. The design is modular; it is easy to add an extra speed to the gearbox or swap gear ratios.
It would also be possible to use (mini)LA’s or small pneumatic cylinders. A design with the bottoms of the modules fixed together would also be possible
If there is enough demand for it I will make instructions or demonstrate different setups.