Bill,
Before we got our CNC back in the late 90s we used to do exactly what you are suggesting. I even had a custom set of bearings made for the shaper that go from about 2 1/4" diameter all the way up to about 10" diameter. With a given cutter head we can flush or rabbet almost any sizing issue that we encounter.
Once we got the CNC we sent hundreds of curved moulding templates to the recycling station as the flushing/rabbeting offset shaper steps were no longer necessary. The CNC eliminated dealing with the templates, cutting on the bandsaw and the shaper bearing step. All in all this was a huge savings in time and labor.
However this process would have been worthwhile if we were just making one occasional moulding. Given our volume though the CNC was a significant improvement.
If the original poster is just making a few of these legs I agree that your suggestion is the way to go......especially if he isn't set up to do this type of thick cutting on the CNC. However if this is a large production run then he will be way ahead in sorting out the tooling/hold down issues.
BH Davis