In the entire history of the BWL and the BSF, only one person got to wear both Championship Belts at the same time: Kim, who was BWL Champion at the time she conquered the BSF sexfighting Belt on January 16th, 2011. She was Dual Champion until she lost the BWL Belt on May 10th and the BSF Belt six days later.
On August 7th 2014, BWL Champion Myriam tried to repeat that exploit by challenging David for the Title. Lucky for him, he had the record holder on his side!
I loved this story arc.