The Dupont estate, known as the Hagley Museum & somethingorother, might
fit your description, as would the collection of mills etc along the
Schuylkill River (Phil Scranton recently published a book on these latter,
I believe).  In the case of the Hagley, it was a one-family paternalistic
situation -- the Schuylkill group was more diversely owned & operated.
 
--bayla