One of the best things I've ever tasted was a serendipitous combination that arose from necessity. I had some leftover pulled pork but had used the last of the buns. I did, however, have some flour tortillas. So I put some pulled pork on a tortilla, added a bit of a homemade cooked salsa that included apple cider vinegar, and rolled it up. I was expecting a clash of flavors, but I was hungry and willing to risk it. Turned out everything went together absolutely perfectly. It was like the universe intended for these things to go together.
This was a long time ago and I don't recall what kind of rub I used on the pork butt. At the time I was just as happy to smoke 'em naked so it's possible there was nothing but salt and pepper. Were I to aim for this usage I'd probably use a fairly normal rub but go heavy on the cumin and not slather with mustard first. I'd also consider injecting with a mix of orange juice and lime juice.