I believe this is part of the new recipe for the Elaborate (required Lvl 65) Cultural Silk armor. I do not know what the recipes are yet, though, as I've never bothered much with tradeskills.
Hopefully, this means the days of paying a minimum of 50k for a single Coarse Spider Silk are over. It'd be nice to actually find Elaborate Duskwoven for sale in the Bazaar at a reasonable price.
Dropped in MPG, off of multiple mobs (huvuls, lightning warriors, discordlings, elite kyvs, and dragorns). Can't remember specifically which mobs, though. Haven't tried any tailoring combines with it, so dunno what exactly it makes.
Had this drop off a water gobby on Suncrest and a Regrua aggressor that wandered by, anyone know what it's for? Eqtraders.com doesn't even have it in their database yet.