The New Yorker has an absolutely fascinating account of 'spy novelist' Quentin Rowan's journey to acclaim using extensive plagiarism mashups all the way. He's got to be one of the most skillful, hardest working plagiarists in history. Rowan cooperated with the author of the article, so it gives you something of a glimpse into his mind.
In response to an apology from Rowan, one of the many plagiarized writers, Charles McCarry, wrote the following to his publicist:
Poor guy—all that cutting and pasting and no joy.
Pretty good editor, obviously . . .
p.s. You may want to add: “He has done me no harm and I bear him no ill will.”