Complete shot in the dark, but I wonder if you contact a local disability rights group and ask if they have a school they can recommend? Give them a two second rundown on your situation and tell them you're looking for a sympathetic school/principal/counselor that can assist you. Maybe one will be immediately obvious to them, or they'll spring to action and help find a situation that works for her.

I think it's completely discriminatory that it's up to YOU to figure out who will agree to let her test there. Not everyone fits in the box, it's that simple. You would think there would be a procedure for the "what if"s. I'm sorry, I know how emotionally and physically exhausting a fight like this can be.