I also know a great maker who can produce a complete violin in a week.
Obviously this isn't possible with a slow drying varnish, and it assumes a level of tool skills that can only be achieved in childhood or adolescence, and absolute concentration on the task at hand.
For quite a while we worked with a maker in Reghin who produced 5 white instruments a month, with no power tools apart from a small bandsaw. But he used an outside mold, worked on several instruments at a time, and as far as I could tell he had no outside interests or demands on his time.
These days I find it difficult to write a 5 minute Maestronet post without breaking off to do something else