I'm a little confused here. What is his official stance? If he wants them to trade him then why hasn't he signed the tender? If he wants a new contract, has he said so?
He signs his tender and the Panthers can ship him anywhere they want without his permission or even knowledge until the trade is complete. By not signing his tender, he is free to negotiate with any team he wants and get the deal he wants and then facilitate the trade between the two teams.
Also, if he signs the tender, he must participate in every organized team activity (including minicamps, OTAs, training camp) or face a fine. If Peppers wants to be traded the last thing he wants to do is go to a minicamp and get an injury. Even if Peppers gets traded somewhere, there is no guarantee that he will be traded before training camp. It could end up being a last minute thing due to injury like Jason Taylor was last year (granted that leaves the Pats out of the mix because they aren't going to wait that long to trade for a player changing position and needing to learn the defense).
Signing the tender would be the worst thing he could do. The only franchised player I have ever heard of signing the franchise tag before he was traded was Cassel. Word is he is regretting it now because, other than a bogus report that he has a long term deal, it looks like Pioli is content to let Cassel play this year under his franchise tender and roll the dice on whether he is a boom or a bust.
I don't get why people are so hung up on him signing the franchise tender. Not signing a franchise tender before a deal was made has never blocked a franchised player from getting traded.
That said, this news is non-news. Most franchised players do not sign their franchise tender until they are either traded, given a long term deal, or around the second week of the preseason. A franchised player who hasn't signed their franchise tender cannot work out with the team because officially they are not on the team. The team holds their rights, but they are still free agents.