I've been listening some of the Martial Arts Lineage Project podcasts and there are two with Kempo instructors.
The first was with Senior Grandmaster George Pesare, the man who brought Kempo to the East Coast. Grandmaster Pesare was Nick Cerio's Kempo instructor and the first person to promote Cerio to Black Belt. A lot of good "no shit, I was there" history in this interview.
The second was with Shihan John James. Shihan James was a personal student of the late Grandmaster Nick Cerio and was one of the people selected by Cerio to be on the Board of Directors of Cerio's Kenpo after Cerio's death in 1998. I exchanged several emails with Shihan James around that time. He was always polite and very much a gentleman of the old school. That came across in this interview.
I recommend listening to them both.