I remember the story fairly well-- there was a young Native American girl whose family (or tribe... idk) lived around or with a herd of horses. I believe that one day she fell asleep on one of the horses, or something like that, and ended up lost. There was a storm at some point, too.
What I remember most is the art work. It was very 2d, not very realistic, and the horses usually had big, round eyes. The little girl had a braid in her hair. Most of the horses were paints, and the pages were full of color.
The book itself was over sized, but very thin.
Any one have any idea?