The time to have made a trade for Carmelo was at the past trade deadline, where Danny could have used Amir Johnson's contract to help match salaries. Correct me if I'm wrong, but I don't believe a team is allowed to combine other players in a sign and trade, to help match salaries. So unless a third team is involved, I don't see how trading for Carmelo is even possible, while still holding onto our core pieces.
Count me as someone who would like to see him in green. A change in scenery, and going to a winning environment, would help him tremendously.