Actually I made a mistake. It was Jim Dixon, not Jim Mitchell. I do not know about this Jim Mitchell dude.
The Lewis footwork is primarily what he developed alongside Bruce Lee and used in the ring as well as outside the ring. It is comprised of methods of delivery to bridging the gap (something Lewis is a master of), like stagger steps, angular attacks, deceptive penetration, broken rhythm and set point control. Most of it was tactical footwork on how to "get off" before your opponent. It is some really amazing stuff I must say.
In fact there is the possibility he might have been doing these things before he came into contact with Lee. Though there is no way to really prove it.
Interesting. Is there any reference material or videos demonstrating some of this? I am curious as to how it is different from what I have been taught in Kenpo.