I wanted to bump this thread for a rec: The Girl Who Circumnavigated Fairyland in a Ship of Her Own Making. I think its Lexile is 850 or something, which isn't accurate, IMO, because the vocabulary level is incredibly high. DH and I actually had to look up two words (one was "widdershins"; I forget the other). DD is really enjoying this book and it's stretching her vocab immensely.