I'm not seeing a reference to "Document Library" in the slide deck you linked to, nor have we created a packaged application with that name. If it was referenced in an earlier version of the slide deck, that was an error. (And, of course, there's the disclaimer on slide 3.)
As to our plans: to date, we have not been upgrading any old applications to our new system, instead focusing on building new applications that we felt would be useful. That said, a Document Library does sound like it might be a very useful application; would you mind spending some time detailing what sorts of features you'd like to have?