I have made a document describing what is needed to port the OWB CMake scripts to Windows. As of now this document describes what I will guess is 90% of what's needed to make the CMake scripts portable to Windows. The remaining 10% consists of a couple minor problems I haven't solved yet and also the last things needed to produce a successful link. I am submitting this now instead of after I have a link because I need to leave town for a couple days and have been meaning to get this submitted since last week.
I have implemented everything in the document on my personal machine, as well as some source code portability modifications which I have submitted as separately ticketed bugs.
Note that I am using CMake 2.6 for Windows and so my modifications also include CMake 2.6 compatibility changes (there are only a couple).
I have attached the document "OWB Notes.html" which describes everything, as well as some relevant CMake-related files.