I recently came upon SAP Press, an imprint that seems somewhat new.  They focus on titles around SAP and NetWeaver. 

They have a number of books on risk and compliance – see http://www.sap-press.com/categories/Governance%2C-Risk%2C-and-Compliance, which seems to be of value for anyone needed to secure or audit an SAP environment.  There does not seem to be any titles specifically around SAP security; which is a book though that is sorely needed. 

I hope to write a review of some of these titles in the not too distant future.