(Sorry this is kind of a big post.. When I start looking at pretty things it's hard to stop and I'm kind of a reference machine.)
The other day I remembered the sculpture artist that I drew a lot of reference from for Treebeard during character design: Romain de Tirtoff, who went by Erté (french pronunciation of his initials, RT). His work isn't really reminiscent of any of the fashion or timeline decisions we've made, but I was really inspired by his use of form. I think he has a really thoughtful and beautiful way of handling shapes that would be interesting to consider for how elements in the environment or her clothes/hair move.. Not to mention it would be a really strong contrast between the ethereal world and the flat, dull reality.
So here are some pictures, that if nothing else are fun to look at :)
Some of his paintings are fun too:
Someone made a stained glass version, with teal!