To my great surprise, I noticed today that a Russian grocery has opened in Centreville, in the shopping center opposite the library (next to Ambala Bazaar). It seems pretty new, since it gives the impression of not yet being fully stocked, though this could be a nod to the old-style Moscow stores with half-empty shelves. They have an impressive selection of frozen pelmeni, nice sausages and other cured meats, and cookies. They also had reasonably priced caviar. I think it's called Moscow Gourmet.