After your observation of the different peppers I wanted to see the difference for myself. Not that I am doubting your knowledge, but just to check it out. Well, here is what I came across.
From Wikipedia, the free encyclopedia
The Naga Jolokia (also known as Bhut Jolokia, Ghost Chili, Ghost Pepper, Naga Morich) is a chili pepper that grows primarily in Bangladesh, but also in northeastern India (Assam, Nagaland, Manipur), and Sri Lanka. In 2006, it was confirmed by Guinness World Records to be the hottest chili in the world, replacing the Red Savina.
It is called Naga Morich in Bangladesh, Nai Miris in Sri Lanka (Nai = 'Cobra', Miris = 'Chili'; in Sinhalese) and Bih Jolokia in the Indian state of Assam (Bih = 'poison', Jolokia = 'chili pepper'; in Assamese). Other names are Bhut Jolokia (Bhut = 'ghost', probably due to its ghostly bite or introduction by the Bhutias from Bhutan poison chili), Oo-Morok in Manipur (Oo = 'Tree', 'Oo' pronounced as in Book, Morok = 'Chilli'), Borbih Jolokia, Nagahari, Nagajolokia, Naga Moresh and Raja Mirchi ('King of Chillies').
But.... thats not saying anything because Wikipedia has a reputation for being wrong with their info.