The thought's crossed my mind before. I think there's scope for implicitly rationalist fanfic there, given the characters' powers and interests, but explicitly rationalist would be difficult to pull off; the story's strength lies in characterization, and bringing anyone too far out of character to make a point would be poorly received. In particular, you couldn't get away with tweaking the viewpoint character the way Eliezer and Alicorn have in their respective universes.
The alternative is an OC session, where the mechanics are used but the characters are different. In that case, if you did use a Rationalist Premise, it would almost certainly end up as leisure reading for people who are already familiar with the concepts (as opposed to leisure reading for people who are familiar with the canon but not the concepts). It would not be Useful.
It would be interesting as entertainment, given the existing composition of Homestuck and the sheer ease at which the game can be twisted out of recognition, but most of the reason I don't is because I can't model people like that.
There was a recent discussion considering the idea of a monthly Book (later expanded to movies, links, etc) thread. The poll was pretty unanimous that this was A Good Idea (tm), so let's give it a try!
Post what you're reading or watching, and your opinion of it. Post recommendations to blogs. Post whatever media you feel like discussing!
I encourage minimal down-voting in the comments here, because this is a thread for sharing subjective experiences, and I would like people to feel comfortable posting their personal opinion without fearing a karma backlash. If you disagree with a person's recommendation, respond with a comment instead.
I think this is a post that lends itself to comment trees, so I will start one with the categories: Books, Movies, Other, and Meta.
I am interested in hearing if you all think it's a good idea to separate out fiction and non-fiction. (So that the Book thread doesn't have Discworld next to Influence, for example. Or so the movie thread doesn't have documentaries interspersed with rom-coms or what-not)
Poster's Note: Wheee! I made my first working link on the discussion post writing interface! I can learn stuffs!