Well, if you're willing to go over to Shirlington, you can get brunch on Saturday morning at the Carlyle Grand. It is a chain (part of the Great American Restaurant chain), but it's still pretty good.
We also love Luna Cafe in Shirlington. They don't have a specific brunch menu, but they do have breakfast and lunch options. Probably our favorite restaurant in the Shirlington village. And they open 9am on Saturdays.