I believe the statement about really long books was directed at people who were deliberately setting out to imitate etc., rather than people whose books were good and long.

As other people have said, really long books get split these days. Westerfeld's _Succession_ and Wright's _The Golden Age_ were oft-mentioned in this regard.

Yes, thank you, a definition that includes Lymond and Wimsey just isn't any use, it seems to me, though I don't see why there couldn't be cross-gender self-insertion. Possibly more on this later.