No way they don't get more for Butler. He is still pretty young, and one of the best all-around SF's in the league, who is actually signed to a decent contract. And unlike some of the other guys being discussed, he really has no red flags that are knocking down his trade value.
Anyways, I don't think they trade Butler anyways. I think he is available in the respect that they are taking offers for ANYONE, but it would take an over the top offer to pry him free.
Now, Richard Jefferson...that's another story.