Is anyone using a front axle to speedometer , cable driven unit ?   Something like the Honda 550- 750 models from the seventies were driven off the front axle, and had 19 inch front wheels also. Some Harley models used that system, but I don't know what years.  Seems like something like that would work , even if the existing axle spacers had to be cut down to make room for the drive gear. Any suggestions  ?

Go to Partzilla.com and search - 90% of bikes from Japan until the mid-80s had speedo drive off the front wheel, and most bikes above 450cc had 19in front wheels.