Rotors are turned on a lathe that is designed specifically for the purpose. Any automotive machine shop and brake shops have them.
As far as this vibration goes, I would be willing to bet that all these rebalances that did not remove this problem were done by putting balance weights ONLY on the inboard rim lip. The tire stores commonly will not put weights on the outboard lip because they have scratched a wheel at one point or another and been chastized for it.
These suspension systems are nimble and a dynamic imbalance will cause a vibration at high speed.
To correct this, find someone who will properly balance with a computer balancer and put weights inboard AND outboard. In 9 cases out of 10 this will correct it.
I got so frustrated with the tire stores that I bought a used 1001 Coats computer balancer, and now every car I have is silk smooth. Using the balancer is not rocket science, I could teach a high school kid how to use it in thirty minutes. The problem is that they always want to static balance which actually aggravates the dynamic balance.
Have a great day,