How badly do they want your dd at their high school? Could you contact another high school to see if she could attend that school instead if the other school would allow this and the assigned school would not?
Another thought is that, if your dd got a 27 composite score on the ACT in 7th grade, have you considered applying to DYS with that and a portfolio if you don't have IQ scores? They could probably help you advocate better than you could do alone.
I suspect that part of their reluctance is that they don't want to set a precedent for other students to request the same. Having your dd in DYS might help them around that issue. If they could say that this concession is only available for profoundly gifted students who are in a program like DYS, I bet that they'd have few, if any, other students who could meet that hurdle and request the same accommodation.
Also, have you gotten the district GT coordinator or her middle school teachers involved in helping you advocate? This would obviously be faster than waiting on DYS b/c you won't be able to make that happen in time for an April schedule finalization.
