I finally just made time to read the example you gave by Julad... honestly I didn't read the entire thing, because it is really late here :) But I think I have more of idea of what you are looking for now.
Seems like a great idea and I would be really excited to read these. I wonder if there is any way you could somehow work this in with fanfic reading club... like when a story is being read and discussed there then ask the author to follow up by doing this. You could even hit up past authors... Or you could post a story at retread and then ask the author to do a post here a few days later...
Might help make people feel more comfortable doing it if they are invited plus it could get the ball rolling.