Ohh, this is like breaking the fourth wall for bookworms.
I hadn't heard of either of those books you mentioned, but I have to go and find them now. That's really amazing—I remember reading
The Neverending Story and being enchanted by the two different colours of text—for when Bastian is reading the story and the story itself; sort of how the fiction is extending beyond the words and wrapping itself around the book.
And then Jasper Fforde has this memorable part in his Thursday Next series, in the book
First Among Sequels. There's one part of the story where the main character goes beyond the reaches of the Bookworld, and instead of the story being told in text there's a few pages of comic-book style drawings, with no words, to show what's happening in that place. Very interesting.
The books you wrote about are fairly unusual, and might turn off some readers, but it's interesting how the traditional paper medium is being extended, and it's not just the words that matter to the story, but how they are presented as well. I really love the idea of highlighting the word 'house' in blue ink and the proofread pages, as well.
