Specifically to the PDF and book as a package:
Could be done. However, it's not wise to do until the digital rights management questions are answered and I'd bet that there's some team at WoTC working that. I'd be surprised if it's not in play and resolved within a year or two. But make no mistake, a global drm legal project takes a good amount of time for a small company that uses multiple distribution methods. Especially if they're dealing with cultural issues internally.
Two cents. I really have no idea what the culture is over there or what they're working on, but I get what could be in the way of stuff, hence why I'm just not sweating it and playing my game.
I'm thinking DRM for written word products will end up much the same as for music: market pressure will eventually push companies to drop the digital restrictions on their product and go back to the near universally usable and accepted format, the PDF (.mp3 for music files). When it does, they can focus on selling product, rather than stopping the inevitable.