I have completed a preliminary version of this simple DOCX generation system, which you can download, unzip, and try. You can find the zip file that contains all necessary bits here.
This post is the eleventh in a series of blog posts on generating Open XML documents. Here is the complete list: Generating Open XML WordprocessingML Documents Blog Post Series
The following 90 second screen-cast shows how to run the doc gen system after you download and unzip the zip file.
The following 2 1/2 minute video shows using the document generation system at scale. I show generating 3000 documents in under a minute.