I've had a conceit in mind for about two years of "what if Shawn and Gus didn't know each other growing up and then met as adults?" The show actually kinda sorta got there before me with a section of the last Christmas special, but I still think it would make an interesting fic. You know, you find yourself asking 'how would Shawn be different? how would Gus?' One of the problems I envision is that I firmly believe Shawn would be close to unbearable without Gus, so there'd be this intensely obnoxious character you'd have to somehow develop and redeem. (Of course, I also think Gus would be somewhat unbearable, only in different ways. Have I ever mentioned how I love, love, love Gus, but occasionally don't like him a whole lot?)
The only thing I've actually written on this story is: Shawn is thirty-three and has never had a close friend. He makes friends well enough, for at least a week or two. But he doesn't know how to keep them. One day, he meets Burton Guster.
Reason(s) for not having written: Lack of time, mostly. Also, there are so many questions, too many, I think. I've long got over starting with one idea and then writing away like a fiend until I figure out everything else.