You have heard the rumors in the past, and here is one more to hang your hat on, this time from the French language site
SithClan.net.
The basic jist of the article states that they believe that this version of the Dark Lord of the Sith will be a deluxe figure that includes his personal meditation chamber. They think that Hasbro will be making a decision soon as we are surely near that incredible #500 mark. Who knows, maybe it will be a little teaser early next year in preparation for Vader to return to the big screen!