Alexandria is effectively sold out and has been for some time---I don't think they are in active sales there anymore. National Harbor, despite a lousy locaiton and not even being open yet (it opens in Feb 2010), was 40% sold this past summer, selling into the teeth of a nasty recession.
http://washington.bizjournals.com/washington/stories/2009/06/29/story5.html
That doesn't sound so bad to me. On the other hand:
This is a big problem for Disney. They just haven't translated well outside RCID's boundaries. They do keep trying though.
Edited to add: I suspect they are going to see how HI moves before making a final decision on the DC property. If HI does poorly, the DC space may be a conventional hotel.