Recently Nintendo-Gamer interviewed Hiroyuki Takahashi of Camelot Software Planning. Here's the relevant excerpt from the article.
In response to this, a group of people took the reins and formed Operation Sunrise, a group dedicated to getting the fan input to Camelot for this game to happen.NG: Camelot also made the amazing Golden Sun. Dark Dawn ended on a massive cliffhanger. Any plans to tell us what happens next? Don’t keep us hanging!
HT: I’m very pleased that you enjoyed Dark Dawn. RPGs take a very long time to make and need a lot of effort. As you will appreciate if you have played the game, the number of ideas that went into the story was rather substantial. When writing a story like that for a Golden Sun game, I really feel like I am pouring my soul into it and when I am finished, I always feel really drained. Everyone else working on the project also really devoted themselves to it, treating it like their life’s work. So it really is a huge encouragement to us to get a positive reaction from the people who play the game.
A big reason for us making RPGs comes from the requests from all the people who have enjoyed our RPGs in the past. Perhaps if there are enough Nintendo users asking for another game in the Golden Sun series, then this will naturally lead to the development of such a game.
Speaking personally from the perspective of the story, I think that honestly it may not be so likely because Golden Sun really requires a full effort to be put in. But of course, if there are enough people saying that we really must create another game, then we may just have to listen to them. Still, you would need to give me a bit of time to work on ideas for the story before we could release a fourth game in the series.
If you played Dark Dawn, you'd know it was a rather poor excuse for a Golden Sun game; it was easy, you really got moved along places, there were 2 points of no return, etc etc etc. You'd also know that it ended on a cliffhanger with the words "The End?"
You can sign the petition that Operation Sunrise set up here.
It already has the backing of Operation Rainfall, which as you know successfully brought Xenoblade and The Last Story to North America (and I think they're getting Pandora's Tower here too, or close to it), so they've got a good ally in their corner.
I just figured that I'd bring it up here, to try to help. :3