I'm not able to answer this for you right now. Once we are given the go ahead to announce these sorts of plans, we will. Despite what seems like a lot of silence, we are making progress.
Also keep in mind, when we say we will release the information, that doesn't always mean the Community Team will be posting it ourselves on the forums. Information can come in many forms from it being posted on the front page, to it being released in a test patch or even in the beta. We do what we can to make sure the information is seen and available to everyone as it comes out no matter the form.

We currently have no plans to implement this. Whether we made them tuned for level 70s or 80s they would be left behind again at some point but don't get me wrong, it's a fun idea, it's just that right now we are focusing on all the dungeons we are adding in Wrath of the Lich King, their regular and heroic versions, along with the dual setup of 10 and 25 person versions for each of the raid dungeons.

Yes, we're looking to add a new Battleground in Wrath of the Lich King. I don't have any additional information on this as of yet