Friend of mine is looking for one (she doesn't own horse, beginner in dressage, living in Carroll Co).
Any suggestions? I can think of Dark Horse Dressage (they have ads in Equiery all the time, have anyone tried it?), but that's pretty much it.
Redeemeade and Woodlawn (spell?) are out of question: I took lessons in both myself while back (before I got my own horses), and I wouldn't recommend either. Waredaca is awesome (I take jumping lessons there), but eventing-oriented, not so much dressage.
Dark Horse is awesome. Janna Dyer has at least one schoolmaster. Christine Betz used to be the trainer there and has since gone off on her own. She has all her medals. Also, even though she was not compatible with Fella Diana Beuchert at Spring Fever is like a classical dressage Guru. And she has Andalusians!