I think Michael Kelly who wrote the Apophis series would be a good choice.
I would also like to see Martin Faulks in an interview since the guy is a pretty legit practitioner of Bardon and Ninjutsu, which is of course awesome. He has some videos on youtube of him demonstrating techniques learned from IIH and his training amongst the Yamabushi Monks of Japan:
[url=https://www.youtube.com/user/MartinJFaulks]https://www.youtube.com/user/MartinJFaulks[/url]
Following on the Ninjutsu route, Masaaki Hatsumi (though he may not speak English) and Stephen K. Hayes would be fascinating to have on as guests, but maybe not up to usual anticipation since the material theyāve released is more along the martial and philosophical side with hints at the occult rather beating you over the head with it. That said, the Ninja do have their own systems of energy working and ritual magic called Kuji-In and Kuji-Kiri which is based on a series of mudras, mantras and ācutsā in the air to augment mental focus, fight prowess and environmental control among other things. But they might be more than evasive in revealing such things since they are NINJAS lol. But anyhow they got this thing where they teach people Ninjutsu through DVDs/online videos:
[url=http://www.hatsumidvds.com/index.html]http://www.hatsumidvds.com/index.html[/url]
[url=http://www.skhquest.com/]http://www.skhquest.com/[/url]
Conversely, this guy Maha Vajra has some resources (books, videos etc.) on Kuji power and other stuff. From what Iāve glanced at he does seem to have a degree of knowledge and understanding of the material heās presenting. Unfortunately a lot of what he offers seems to me outrageously priced under the publication section, but at the bottom of the page he does have some items that are still reasonably priced.
[url=http://www.mahavajra.be/]http://www.mahavajra.be/[/url]
Anyways these are just my 2 cents.