For once I'm not able to find a reference to one of Haruyama's obscure characters. The artist lists this as Aoi from 「瞬足　Lemon Pie」("Madoka Ashi Lemon Pie"). Does that sound familiar to anyone?

I think she's the character of this advertisement anime.
http://www.achilles-shoes.com/lemonpie/index.html
http://www.junior-shoes.com/

Yep--that's her. How like Haruyama. I hardly know where to begin tagging this.