Jason Colman has published "Sustainable Book Publishing as a Service at the University of Michigan" in the Journal of Electronic Publishing.
Here's an excerpt:
To solve this problem [publishing open access books], Michigan Publishing Services has developed both a house service publishing imprint, Maize Books, and a white-labeled book publishing program, branded by University units, all running on the same technical and financial infrastructure. With an emphasis on Open Access with flexible Creative Commons licensing and affordable Print on Demand and EBook options combine workflow efficiencies with a menu of chargeback services to cover the costs of their production and allow staffing to be scaled to meet emerging needs.
This brief case study details Michigan Publishing Services’s program for books as it stands today, explains its approach to sustainability, and offers a few thoughts about when this model is suitable and when it is not.