HI momma2many,
Sorry to hear about your bump in the road. I think private testing is a good idea if budget allows. You will have more ammunition

when meeting with the school.
1. Does your school district/state offer credit by examination?
2. Are there any language immersion preschool/kindergarten around your area? One of the families here sends their son to a Spanish immersion school three time per week, and do math/reading etc. the other two days at home. They figured that at least, the child learns a new language and enjoys some socialization.
3. Since our school is not too crazy about acceleration or early entrance, we are considering taking a year off (oh, I mean "home school"

). We plan to do a little math online, some reading, and whatever DCs want to try: arts, music, sports, cooking, gardening, martial arts, language, growing more sea monkeys, etc. It beats learning one letter per week (again). Not to mention, we can travel during low season without worrying about "your child has missed xxx days...."
Good luck!
PS: We spoke to the GT coordinator for our school district. Apparently, one of the reasons for discouraging early entrance is because the school does not get paid for children <5yo who are enrolled in kindergarten. I know this does not solve the problem, but maybe you can consider asking the school again the day your child turns the magical five years old.