Li Feng and David Branner’s book on writing in early China is now out. I have a chapter which addresses the question of scribal training at the Shang site of Anyang 安陽.
Adam Daniel Smith, “The Evidence for Scribal Training at Anyang,” in Writing and Literacy in Early China, ed. Li Feng and David Branner (University of Washington Press, 2011), 173-205. A pre-print of my chapter is available here.