Me too. We are with Kaiser now but are switching to Aetna Jan. 1. There was a great group (per the folks here) in Ashburn, but when I called I was told no openings and no waiting list. I can't recall the name of the practice right now.
You might want to do a search in both the Metro DC and the VA "Finding Your Tribe" groups. There have been a couple of posts about this, I'm still reading through when I have a chance.
It's a shame there arean't more around- I just found out about the holistic pediatrician association http://www.hpakids.org/recommended_sites.htm and thought there might be some options listed there, but any in MD or VA are not in the DC area- much too far to use as a regular ped. And none are listed in DC