I have spoken to Mark Sullivan in person a couple of times.
I commented on the camera work of his videos.
At that time he told me he had never been able to get the same camera man to do more than one video. He has released a couple of films since then, so that may have changed.
I found him to be very friendly. He is intense, when I talked to him about hunting I could tell he really LOVES doing it. He does it for far more than the money, or so it seemed to me.