Many client access libraries (ADO.NET and LINQ) support CRUD operations for XML. Also, starting with Windows 2008 / Vista, the NTFS file system supports transactional writes. So, an XML document on NTFS and a few hundred lines source code really could meet all the requirements for a full featured ACID NoSQL database.
http://msdn.microsoft.com/en-us/library/windows/desktop/aa363764(v=vs.85).aspx
"Do not seek to follow in the footsteps of the wise. Instead, seek what they sought." - Matsuo Basho