Zach –
To compliment your great article, here is a video I found thanks to a tip from Will Milne. This is a French site but the detail is amazing. There is a video from Cortland about the process of making a fly line. I found it very informative. A bit dated, but cool nonetheless.
Go to this link http://www.jpdessaigne.com/Materiel/Sommaire_materiel.htm#
Then choose La réalisation d’une soie en vidéo
Also, go to the upper left link for pictures of the Cortland factory.
P.S. – the link on Whiting Farms is also great. Very rare footage indeed since Whiting does not allow tours. And that Chuck Norris genre picture of John Whiting is classic (top left)!