Is it possible to ferment chilli-peppers and produce a liquor with a alcohol content and also a hotness?
This isn't quite what you're asking. I don't think chili peppers have enough sugars in them to produce a strong enough fermentation on their own.
I made a chili-pepper beer, which was absolutely fantastic.
I made a simple, low-bitterness beer. After fermentation was complete, I racked into a secondary and added 4 types of dried, frozen chilies. I sampled the beer every day until I thought it was hot enough and then bottled it.
The beer wasn't too hot (though it could have gotten hotter if I'd left it on the chilies longer), but had a fantastic spice at the back of the throat. It was delicious, and went great with summer barbecue.
I believe chili peppers would qualify as an adjunct. I would treat it like any fruit/vegetable/spice beer and add it late in the boil. Start small and increase to hit your target flavor.
Brewed two different ones (both ciders) and they were hits. So, yes you can.