Not having noticed this thread before, I'm glad someone (was that you,
@BAYLOR?) revived it -- even though I don't expect it to go far.
My first reaction to seeing this is to remember Philip Jose Farmer, who I believe has to be considered THE master of pastiches. His Doc Savage effort has already been mentioned, but his Tarzan pieces are, imho, the classics of that "genre."
I must mention, however, that I think this thread suffers somewhat for lack of a definition of "pastiche." Nor am I sure I actually
have such a definition -- all I can say, at least until I think further on it, is that I have a reaction that some of the works that have already been mentioned in this thread don't
feel like pastiches to me...
As an example: three of Ted Sturgeon's books were cited as falling into this category. But as I understand them, they were "novelizations," which in my mind is a separate category -- that is, they were an example of someone producing a "novel" based on a movie that was produced from a script -- and usually such things are done at the behest of the movie producer, in the hope that it will make a little more money (if the movie is popular, people will be tempted to buy the book; and if the movie doesn't do well in the box office, there is a hope that readers of the book might be led to it...)
Or so I understand.
Nor would I consider Brian Herbert's work to be pastiches; to me, they seem to be attempts to continue Frank's series -- to me, that's not "pastiche" (just as a book I wrote --
Antagonist, which appeared with Gordy Dickson's name on it as well as mine -- was not a pastiche, but a continuation...)
All of this, please understand, is solely my own opinion; I'm no expert on this kind of thing, and I've never had occasion to think about it until just now...
Feel free to jump on me with both feet, should you disagree -- I won't get mad.