[rotorwrench]

A good driveshaft shop can quickly fabricate any shaft that you could need. They will even balance it. Dana Spicer u-joints are available in different configurations and sizes. If a person measures a slip yoke and rear axle drive flange for diameters and widths across the yoke surfaces, a size and configuration will become apparent enough that a u-joint can be sourced. If you know what vehicle types and models the yoke and rear axle are from then you have a way to source a u-joint to fit both ends. The drive shaft shops know what knuckles or yokes will be needed to make up a new shaft for a given u-joint type.