Valerica can provide you with soul husk extract. I think I remember getting it from her once. More of a collector's item than anything useful. And I'm afraid you may have to pluck a couple of wings.

My bunnies slaughtered stat accidently got incremented when the poor thing ended up too close to a melee. Oh well.
Wait, there's a "wings plucked" stat?
EDIT: I'll be darned. Can't believe I hadn't noticed that 'til now. Great, one more thing for me to obsess over.
Updates:
1. No sign of any ancestor moth wings - or
any of the new ingredients - in any merchant's stock. Now, I only went to each one once, but for
none of them to have anything (there are 6 alchemy merchants I went to), I assume the new ingredients weren't added to their inventories. And, BTW, I did go back to the glade just to confirm that they can be plucked. Sure enough, every now and then a moth in one of the swarms has the option to catch it, which removes it's wings and adds to the dreaded "wings plucked" stat (only slightly less frustrating than the "bunnies slaughtered" stat).
2. Okay, so no vampire lord armor for me or anyone who doesn't side with Harkon.
3. Ooops... had the soul husk extract potions (4) stored in a chest. Sorry. Don't know if they respawn in the Boneyard, but I'm willing to bet they aren't sold by any of the regular merchants!
Thanks.