I'm not convinced it's actually possible for an e-liquid to be spicy.
Let me caveat that by saying that I've cooked with Ghost Peppers, that it usually takes me 3 or 4 visits to a thai or indian place before they'll believe me when I say "as hot as you can make it", and haven't had anything "too spicy" since I was about 11
the only thing I can find that I can't do is wasabi, and that's just because the flavor is gross. But I also haven't gone out of my way to find some of the few strains that are hotter than Ghost Peppers
reducing the vinegar out of Dave's Insanity or Ghost Pepper sauces to use on hot wings works well enough when I need to shock my sinuses back to their senses.
Anyway, the way spicy foods coat your mouth and tongue isn't just an instant chemical reaction
there's actually something that sticks around. Plus, as hot as foods can get, I'm sure I wouldn't want to breath anything like the stuff I eat. Cooking with ghost peppers sends my girlfriend and the pets running for the hills, and I've made my eyes water from a blast of air when cleaning woks and pans before.
As much as it seemed like a good idea a while ago, I just don't think a juice that's actually spicy would be a good idea.
I kinda want to try mayan apocalypse (+ extra chilli) at some point, but pbusardo's review mentioned it tasting mostly like chocolate and paper. And the idea of vaping chocolate already turns my stomach for some reason.