Question for out of U.S.r's (KPH)

[nu2-72]

I have been speaking with some folks across the pond.
They drive in Kilometers and we drive in Miles.
With a new dash overlay, a person could change the speedo to show KPH in relation to MPH. Or show KPH only. However, my thinking says that even though the speed shows KPH, the odometer will register miles since both are controled by a single speedo cable.
Does anyone know anything about how to convert a dash to KPH so that the speedo and odo read alike? I would guess that there might be a transmission speedo gear change that would do this since it would change the cable rotations and change everything down line from that.
An overlay would show the correct speed for KPH but at annual inspection time or however they do it, the mileage would still be in miles.
Or was there ever a dash for these trucks made for export that would have the correct components to be KPH? Canada maybe?