I am just taking a shot in the dark here, but here's what I would do: I would up the Scoville unit ante with a more potent, better flavored, fresh chili. I would then toss some of this into a brine that enhances the flavors of the chili, rather than focusing on spice, so that I don't end up with something rancid smelling. Then I'd let that soak - time depending on whether I'm doing pieces, or a whole chicken to later butcher. Then I'd assemble a cautious, standard spice rub- basic seasoning, as burned peppers taste pretty foul, and they can burn in the deep fryer. Plus, their spice would mostly be cooked off. Certainly watch the amount of dairy (not off limits, but stick to buttermilk or less fat, would be my suggestion), and cooking time, as you will cook off your heat. I like the idea of incorporating chili oil, and I like the idea of perhaps having a spiced up liquid dredge portion to the flouring process. Before the frying though, I might look into potentially cooking the chicken sous vide with its spices. Simple to do at home with a zip-loc or similar sealed plastic bag, a thermometer, a silicone pad, and a low temperature flame...and a jug of ice water nearby.
I love spicy food, so this is a good test for me.
Personally, I'm a sucker for sauces anyhow...but I'll give this a go.