The first thing that popped to mind when Amazon issued its Kindle DX was this: textbooks! The size makes it perfect for using in place of those dusty old books, and we're guessing that most students would much rather lug around a single electronic device versus a sack full of heavy books that they'll only read a page or two from in any given class (after class is another story, right kids?). But it seems as if not everyone is too keen on the Kindle DX replacing the textbook, and the National Federation of the