I've had a thought....what about Alison Sudol? I like that she seems to have the ability to vary her look rather effectively. Even though she is capable of looking gorgeous, she could also easily pull off the atypical sort of plainness (by elven standards) we're looking for. She seems sturdy enough and I can easily picture her as a dedicated artist. She has the look of an adventurer, prone to following her muse and delighting in life. I can see Fëanor being drawn to her.
Here are a few of the looks I particularly like:
As an aside, I find she also vaguely resembles this fanart of Nerdanel that MithLuin posted earlier:
Honestly, when I think of Nerdanel, I think of this image of Joan of Arc. I'm not entirely sure why, but something about her...rootedness? appeals to me. I would like Nerdanel to be the balancing force for a spirit of fire, but not in an 'opposites attract' way - she's also feisty, just very grounded and reasonable.