I'm pretty sure my attorneys have dealt with art-related EB-1; for example I remember they helped a Russian ballerina (if I remember correctly) get her green card and have other experience as well.
They are a two-woman team who work very closely with the individual; no paralegals or stuff like that; very one-on-one personal. They may be a little pricy, though less so than bigger firms. Their names are Priscilla Labovitz and Pat Hanrahan (my case was handled by Pat).
Labovitz Hanrahan • 202-291-9648
Priscilla Labovitz and Patricia M. Hanrahan
6856 Eastern Ave., NW, Washington, DC (Takoma)
33 years experience in immigration law.