I would avoid doing flayed heads.
In the show we see a flayed man with his face intact. I suspect it's quite hard to flay someone's face, which is why it's an impressive feat of the Faceless Men. Also I don't think hair would remain very long.
I would also avoid the vague shapes. They would only revolutionize tanneries (we could just revolutionize tanneries), and their use in the Dreadfort wouldn't immediately make me think "HUMAN SKIN". That being said, the full body skin I recommended to you looks mad goofy so I don't know anymore. Looks like someone's fursuit.
We might need to bust out some actual concept art to figure out this room, but here are some ideas:
- Slab block for a stack of skins. Could put them in rows of storage to either side of the room.
- One big (flat) centerpiece (ala Mance's giant antlers block) for a human skin in an X position. Maybe even some kind of tableau that involves more than one skin being displayed. Would go at the far end of the room.
- Hanging skin cloaks. Probably clothes line type block w/ vert CTM, but maybe an X shape like meat for the extra volume. No head, obviously. Like a deflated human balloon.
- 2x2, 2x1, and 1x2 hanging skins. Both newer and decaying. Finding the right look and balance between "vague shape" and "just a foot" is a tough balance though. Maybe someone can provide some good examples here.
Historically (1000+ years ago), Boltons made cloaks and an entire god damn pavillion from skins. So the stitching together of skins is clearly something that happened. Maybe we could get some larger textures of skins stitched together.