One interesting thing about the state of LA is they promise a right to a free, appropriate public education to gifted children, which goes beyond the requirements of IDEA and similar federal legislation. In concept, it's quite laudable. So now we're trying to leverage that right into what's truly appropriate for her.
From what you've described, the people you've dealt with aren't interested in meeting you're daughter's needs. So you need a new strategy. They work in a bureaucratic system and I recommend that you use everything that system has to get what your daughter needs. My advice is to look up the law on what they have to do for gifted kids and write a letter to her school and the school board that quotes it chapter and verse.
Include the stuff you have in writing that makes your case, like her score on the end-of-second grade test and any teacher notes or emails.
For example, you could go after them on their failure to follow the recommendations of the testing they gave her. Where does the law stand on this point? If she passes a test (you said her reading was off the scale for end-of-second-grade), does the law mandate that they give her appropriate assignments? Or are they allowed to ignore the results and force her to do work that she has already mastered? What about an end-of-first grade math test? Call the office of gifted ed. and get answers to this and other questions. Get answers in writing or ask them to point to a relevant section of the law.
If the district has a policy on grade skipping but the principal made a blanket statement saying he'd never even consider or allow it, use this as part of your argument that they have no intention of meeting her needs (or those of any other gifted kid for that matter). Do you have his statement in this regard in writing? If not, get it (send him an email or a real letter asking "Is there any way you might reconsider or some such thing that leaves the door open).
Quote precisely what the law says and give specific examples of how the school if failing to meet its requirements under the law. If they said they differentiate appropriately, give examples of how their idea of appropriate differentiation isn't meeting the standard set by the law. Quote the Iowa manual and respected reports like
A Nation Deceived. Etc.
You may have to accept that in order to get what you want, you're going to have to annoy them or make them angry with you --- primarily because it sounds like they're going to have to be forced to help your daughter.
I understand that NCLB has mandates that discourage helping gifted kids, but if the law says they have to help her, it's too bad.
Final advice: write everything down (ask JonLaw about this). If you rely on verbal conversations, people can have different memories or interpretations of what was said.