Was thinking about PA stories and thought of one I'd love to see: a worldwide apocalypse kills mostly adults, leaving young kids.
You could have a small handful of (young) adults, but the majority would be relatively innocent kids having to fend for themselves and trying to both grow up and figuring out how to preserve a civilization they never quite figured out.
Obvious bad guys: the few adults who 'lead' groups of kids for their own benefit, taking advantage of them.
Unfortunately for most SOL authors, the chances of a sex story are few (other than the few teen (14+) adults, but for a story like this, it would be natural for budding romances to blossom, but for the kids to be too 'scared' of taking it to the next stage. That means lots of romance and character development, but little explicit sex.
I'd write it myself, but I've about played out my PA stories, and I've already committed to writing yet another Apocalyptic story (featuring yet another telepathic dog). If anyone is interested, feel free to run with it, or even run the idea by me if you want further ideas.