Building the Great Cathedrals started airing last night on PBS stations. I haven't seen the whole thing yet, but here is the trailer -
You can see the whole online video here - Building the Great Cathedrals. Though stained glass is mentioned throughout, the one segment dealing directly with stained glass is short, from about 34:15 to 38:00.
My first general impression - much to like and much to drive me crazy.
I hope to elaborate later.