Here's an interesting article from NPR: Hybrid Books: 'Illuminations' And The Future Of The E-Reader
Brooklyn independent publisher Melville House, is offering/touting Illuminations. "Often the Illuminations are longer than the book itself, stuffed full of illustrations, maps, articles, photographs and historical documents."

The idea is interesting in that it provides a bridge between the e-book and print copies (both come with "Illuminations"), and gives booksellers on the frontlines more ammunition to use when trying to push physical books.
The comments are very interesting, too -- "The tone of this article and some comments is "Gloom, doom, change is here, we don't like it, woe is us."

What do you think?