Dear Frances,
How about that for a catchy title for a talk. I've been reading Gore Vidal's Julian and there are some interesting descriptions of the employment of eunuch's in the late Roman Empire. Also, the Chinese from what I've read had a whole caste of educated eunuch's who also ran their empire. Considering that this is a historical meeting your speaking at, you might as well be historical.
I agree with Mike Yates, if your doing the work you should be paid the rate. If your working as an instructor you should be paid as an instructor.
You could research some of the more bizarre spending the state of Florida is doing i.e. give a ways to corporations, tax abatements, prison building etc. I'm sure any friendly politician could give you good examples and leads. You could say something like, you can't pay us fairly because the XYZ corporation might not get a 100% tax abatement. That kind of humor cuts deep.
You could call the AFL-CIO Human Resources Department 202-638-3912 ask for Bob Baugh. Tell him about your speech and see if he can direct you to anyone.
I've made a few phone calls and should know more later.
Sincerely and Fraternally, Tom L.