I’ve only read one book by Piers Anthony — I believe it was Shade of the Tree (1986), perhaps thirteen years ago. It was very forgettable, probably even bad, but one bit I remember went something like this:
He hadn’t had a lot of relationships, and those he had had had been bad. Had had had!, he thought. What atrocious grammar!
Or something like that; please excuse any lapses in my memory. Of course there’s nothing atrociously (or at all) ungrammatical about this, and it’s not even necessarily bad word choice.
But I would have suggested that, since the author wanted to go that route, he could have chosen “…and those he had had had had problems.”
(See here for other instances of “had had had been” in books. Also try to punctuate the following sentence: james while john had had had had had had had had had had had the teacher’s approval.)
UPDATE: Oh yes, also what I remember was the repeated use of “welkin” as a synonym for “sky”.