Rankings of book publishers?--Follow up

I have received an inquiry from a communications professor here at Baruch asking for rankings of book publishers specificially in relation to scholarly works in the humanities and social sciences. The publishers are Blackwell, Intercultural Press, Sage, Cambridge University Press, University Press of America, University of Michigan Press, Jossey Bass, Rowman Littlefield, Routledge, Lawrence Earlbaum, Ally and Bacon, Prentice Hall, McGraw Hill and Thomson Wadsworth. If you know of any sources for this type of information, will you please share it will me (and others.)
I will let you know what I find. She is also looking for journal rankings, which I think will be easier to do. Thanks for any help.

To follow up on this posting, I have found some articles about the perceived quality of book publishers that I will review before I send them to the professor, who is currently abroad during research.

The professor is interested primarily in intercultural communications. Following a suggestion by Stephen, I used WorldCat, did a keyword search for intercultural communications, limited the search to a specific publisher, and limited the years to 2000-2007. The detailed records available were emailed to the professor, who thought it was the greatest!

She was also inquiring about the rankings of specific journals and I learned that two have ceased publication and I found the impact factors of several listed on the journal websites, and also through other sources on the web. I am reviewing some journal articles about the rankings of the journals.

Rita