Hello Informed Parent,
We have an excellent State Department of Education here in Colorado which sets the guidelines for Charter schools. Here is what they say online regarding Charter schools and 504;
"Licensure requirements for special education service providers may not be waived. The Individuals with Disabilities Education Act (IDEA) is a federal law that requires that personnel providing the Individual Educational Program be appropriately trained and licensed. It is essential that charter school developers and those involved with them understand that there are no exemptions from any federal or special education law, including Section 504 of the Rehabilitation Act of 1973, Title II of the Americans With Disabilities Act (ADA), and the Individuals With Disabilities Education Act (IDEA)" I don't know about waivers but would suggest you contact Peak Parent Center at http://www.peakparent.org/about.asp-for
more detailed information regarding local schools with "best practices".
Hope that helps. Please feel free to contact me if you are looking for a Realtor who understands families with special needs. Good luck