You mentioned that Schreibner's mill was one of two sash saws in US. There are many more than that. Check out the links at the Ledyard Sawmill (in CT) site at

http://sites.google.com/site/ledyardsawmill/

You will also find a detailed description of the operating water powered Ledyard Up and Down sawmill with videos and technical details, links to 19th century books on up and down sawmills, and other information.

Ledyard Sawmill's Old Woody