JenTris, have you tried seeking out advice from a local group, either a parent advocate group or a disability law group? I was able to find both types of groups in my area by looking through the yellow pages link on the wrightslaw homepage - if you haven't already looked there and need help finding it let us know. I found that the local groups advice was really key in advocating, because they had direct knowledge of the schools and staff personalities we wild be dealing with, as well as being able to give me a reasonable opinion re the likelihood of success and tips on advocating.
Have you tried bringing an advocate to an IEP meeting yet? That might be a good place to start.
My other piece of advice - if you ultimately aren't successful now in fourth grade, don't give up. My 2e ds was also denied math acceleration in elementary school due to us disability, but we after-schooled in math throu 4th and 5th grade, and when he went to middle school we were able to get him placed at his true level by having documentation of his after-school achievements as well as his ability testing.
Best wishes,
polarbear
