I've mentioned this in other threads, and got several supporting posts. Pork butts are big hunks of meat. No matter how much smoke you have, it is only going to penetrate maybe a half inch -- at most. A ten pound butt is not going to have a strong smoke flavor, even after you pull it an mix the outer parts with the inner parts.
A rack of pork ribs will have a lot more smoke flavor, because ribs are relatively thin, compared to a butt. A quarter-inch of smoke penetration on a rack of ribs will give you a pronounced smoke flavor. Smoke can only penetrate so much, no matter how long you expose the meat to smoke -- two hours or ten hours, the smoke can only go so deep.
From my experience, if you want more smoke in your meat, smoke smaller pieces of meat. Smoke has its limits.