You will find many pictures of the Messerschmitt Factory in two books written by Peter Schmoll
1.Die Messerschmitt-Werke in Zweiten Weltkrieg 2004
2.Messerschmitt Giganten
The first book all in german but with many pictures is about the factory itself..lots of pictures.
The second is about the big transport they built.
The website for the publisher is
www.mz-buchverlag.de
Hope this helps
Graypilot