The Washngtonian also has a fairly complete list of restaurants extending RW specials:
They're updating it regularly; be sure to check out the Comments section where people are posting the latest additions to the list. I'm going to try to make it to the Prime Rib and maybe Art and Soul.
Answering my own question, here is a list that was posted previously:
Ici Urban Bistro
Art and Soul
Co Co. Sala
Mie n Yu