Tonight I injected two pork butts with an apple juice/honey mixture and seasoned with rub to marinate overnight for smoking tomorrow.
I'm going to cook one using the standard salt, sugar, pepper, garlic, onion, cummin mixture. I added a teaspoon of chipotle spice (smoked jalapeno) to the rub for the other one. I bought the chipotle a few months ago and have experimented with it off and on. If you ever try it, go easy on it because it's pretty hot.
For comparison, in case you're not familar with chipotle, it's hotter than white pepper, but not quite as hot as cayenne. It also has a smokey flavor that is unlike any other pepper I've ever tasted. I think it would be pretty easy to overdue it.