I kind of agree with Konstantin. Sometimes, its the details that kill what seems like an otherwise good idea
Running the V wheels on the sharp or unmachined corners of standard flat stock is not going to make a good raceway, because there would be an initial state of high wear on both the soft wheel and on the raceway itself. So right away, we get into having to chamfer both sides of the flat bar, and keep every chamfering cut parallel. This task requires a lot of care and attention to achieve.
Then, eccentric studbolts would be required in both wheels on one side, so that the gap can be properly adjusted. While doing this is not difficult, it is
not just a plain old bolt.
As Konstantin said, machining your own V wheel flange is conceivable, it is still expensive and troublesome to do properly. Hardening and then subsequent hard-turning of the wheel would be required. The tolerance for error on the wheel is zero runout. The tolerance for lateral displacement of the V in the wheel flange is also zero, or this will cause tilting of the truck. Just try actually defining the position of a V groove in a cylindrical surface sometime. Its one thing on paper, but a whole different thing on the lathe.