To me, it sounds like you want subject acceleration, not differentiation and enrichment. It sounds like you've spent a year trying it and it didn't work. A year is a long time in the life of your DD.
If I were you, I'd take this tack (and I have): teaching is difficult, teaching to a wide range of abilities and personalities is difficult. Asking a teacher to accommodate your one student is unreasonable. At least, it is unreasonable to ask a teacher to do it consistently throughout the year. It is unfair to the teacher to have to take her focus away so often from the rest of the class. You sympathize with the difficult situation teachers are in. And you think subject acceleration will help both your DD and her teachers. Subject acceleration will allow your DD to be in a class where the teacher will not have to treat your DD any differently than the rest of his or her students. There will be no extra work for the teacher.
I love this tack, and would at that peers are such an important part of learning, that even the strongest differentiating teacher can not provide readiness to learn peers in a classroom where DD is the only child who has her readiness to learn level.
Grinity
