I recently watched African American Lives on PBS, it was a wonderful
and interesting program. I'm white and at a dead-end with my research and to a certain extent, I feel your pain. After watching that series though, it's amazing to find records and information from the slave era. My heart and prayers go out to you on your search. I hope you find what you are looking for! Good Luck!
If you haven't seen this, I'd highly suggest watching as it may help you a good deal in your research efforts.