Just had that one with my lunch. A lot hotter than I thought I'd be =) Very nice looking pods with excellent heat. I can't speak for the origin of the strain....
Who knows what the real story is. I grew a few this year and the heat and flavor are comparable to a Chocolate Bhut. My plants were tall, about 6 ft and most of the pods were rounder, although some looked like Choc. J. Pods drop off easily when ripe. Nice plant.
Not the norm, more tapered.
Black Nagas are a Naga Jolokia Variation, mine do not taste like Chocolate Bhuts at all....closer to a Douglah.Whether it is a natural variation I cannot say..