I completely sympathize... Here are a couple of things we tried (some of which are ethically questionable, so be forewarned):

* I enrolled her in the academic camp they suggested, instead of the one she wanted, but at the end of week celebration button-holed the director. I explained my situation and my disappointment, not with program -- which I complimented lavishly -- but with the wasted money because DD didn't learn anything new (she had that in her biology class last year -- but she's accelerated so...). She now has an exception on file for most class age limits with this organization. We've tested this and got her into an above level class.

* I keep a running list of teachers who I can count on for references. This is critical because some teachers will know how smart she is but still be too worried about 'social issues' to make a good reference. Some seem to be in denial about how old she is. In this case I'm loathe to make them think too hard about the 'kid' in their class, so I don't bring it up.

* While extremely reticent to discuss DDs academic level with random parents or people, I'm completely open about her with other smart people I know or work with. Smart professionals know other smart professionals and can open doors to opportunities. For example, some folks at work were tickled by DD's science fair project and connected us to some expensive lab equipment to borrow. I'm just real deadpan about it, not gushy.

* Forgiveness is easier than permission and sometimes information on forms gets messed up. Once they see DD in action, it's rarely a problem.

* Because she goes to a homeschool co-op where she takes above level classes, I feel comfortable listing her grade along a continuum based on the classes she's currently in for outside academic programs (just as I'm comfortable listing her as her normal for age grade for non-academic camps and social stuff despite the fact that she has no classes at that grade level).

* In terms of the co-op, they are so flexible that things usually work well. I enrolled her in classes where she was only a little young and let her shine. From there it was an easy segue into classes where she was very young... because by then people knew her and what they can expect. And I'm super respectful of the teachers, reaching out to validate that things are going well and there aren't any issues.

And just a note. This is VERY HARD in the younger years and gets better as time goes on. DD is hovering on the edge of teenagehood and puberty. People are more willing to have broad age ranges for offerings and she can pass as a smart young teen. In fact, she feels very much like an underdeveloped 13 year old, so much so that we have to put the breaks on social stuff (no, you can't go to the teen dance, even if your friends are all going).