I have spent most of my working life as a commissioning editor, helping to prepare publishing proposals for various publishers.
For a very good explanation of what a commissioning editor does, see
http://www.prospects.ac.uk/commissioning_editor_job_description.htm and http://en.wikipedia.org/wiki/Commissioning_editor (See examples of books below.)
Please contact me if you would like to submit a proposal.
Examples of books that I have commissioned/edited/project managed/typeset: