We mill concrete with a standard drum (5/8" tooth spacing), with machines as you mentioned, on a regular basis and get good results. There are "concrete" teeth that can be used, but if it's not too hard or abrasive, we have used the same teeth we use on asphalt. Production is considerably lower in concrete than in asphalt milling, so the bids are priced accordingly.
While I don't have experience in milling for white topping streets as you describe, I have milled bridge decks for concrete overlay, and streets for asphalt overlay. In those situations, we can mill to spec up to 4" without much trouble. Again, this depends upon the existing material. I've milled concrete to 1" depth that has given us more trouble than 4" milling of concrete in another location.