Feathered Friends offers eVent fabric as an option on ALL their sleeping bags even the Osprey/Kestal +30 degree series.
I asked about eVent when I was shopping for one, I have a Kestral, sized long in Epic. And eVent is also an option for their down Jackets, Parka's and down pants.
I have a Nightfall, +45 degree, 800-fill power down bag from Sierra Designs which weighs about 2.5-Lbs. The shell is their own Dry Zone WP/B fabric. I call it my hybrid bag, I bought half off at Campmor years ago.