Always felt that skulls inevitably sitting in a pile or made into a chair/cup was a bit boring, but I'm thinking there may be a few fun ways to spruce that up, so here's a few ideas.
Allow the inspecting of skullpoles and skull thrones to see the names of the skulls used to make them.
Add a wound, 'Shamed by Ancestors'. If your ancestors are desecrated in such a way to become a chair or be impaled on a spike, your current character should have a permanent 1hhp wound much like the realm one. This wound would also allow a low cost hearth magic that would seek your ancestral remains so you can free them from their ghostly torment. Maybe killing your ancestors' killer would work too.