http://www.nps.gov/natc/historyculture/williamjohnson.htm
He was born a slave, freed by his master (who also freed his mother and sister), became a successful businessman, and went on to accumulate 16 slaves himself! I have not read his diary but will have to put it on my list.
http://www.amazon.com/Barber-Natchez-Edwin-Adams-Davis/dp/0807102121
I remember on one of my trips to Natchez in the early 90's that they had just begun to renovate his house.