We had great success in a small rural charter school where the principal seemed to really understand gifted kids and allowed them to work at as close to their level as possible by either accelerating a full grade level or subject acceleration.
It is so dependent on the people at the individual school - both teachers and principals. Right now we're at a small private school with DD#2 and are just starting to get some of the accommodations we need. The teachers don't really seem to get it even though the admin does.

Good luck on your adventure - it is always interesting to see where you end up when you make a large change like a move.