Don't include exhibition bouts. I'll start with the two. Saoul Mamby - http://boxrec.com/boxer/235: last fight - at the age of 60 years and 9 months. Lost by decision in 10 rds Levi Forte - http://boxrec.com/boxer/235 last fight - at the age of 58 years and 10 months. Lost by decision in 4 rds
The Great Gianfranco Rosi made a comeback and fought at 49. Bronco Billy Wright was fighting at 51, might still be active.
Mamby looked great in that video at 61 yrs. old. He had some big paydays when he was WBC 140 lb. champion hitting the road to fight local heroes. But, he was promoted by Don King so who knows how much of the $$ Mamby actually got. I think Mamby is underrated and forgotten. I remember even in his 40s he had enough left to beat Gary Hinton and Glenwood "the Real Beast" Brown, who were good fighters.