Some things I'd try:
reach out to any network you have--a local gifted mailing list? local DYS parents? --and see what you can find out about the TAG program. It probably would be an improvement over your local school but you may be better off pushing for one of your other options.
if your appeal isn't granted I would consider going up the administrative chain -- the school board? is there a disability office at the state level?
could you manage to homeschool for a year?
when will you find out about the TAG programs in other districts?
I really, really feel for you because our first school also had a terrible principal that refused to allow accommodation for my 2e PG child. We finally moved. Next year (4th grade) will be her first year in a TAG program even though she'd been PG and needed advanced curriculum for years.
