I second what Grinity said. In MD, Johns Hopkins Center for Talented Youth is the place to go for testers who are accustomed to gifted kids. But it comes with a high price tag. The minimum is about $1500-2000 with additional fees for additional tests. It sounds like it might be worth it from what you are describing.
University of Maryland also does testing through their ed psych department for about $500, but those tests are with supervised grad students who are learning how to assess children. It's an option if money is an issue but might not yield the same insights as a more experienced tester. It's called the PEER program.
http://www.education.umd.edu/EDCP/page.cfm?section_ID=11584025503022008&page_id=170143234101420091Good luck!
