I want to create a variant on that for rationality topics; not "giant sci-fi nerds living together"; but "giant rationality geniuses" living together.
and I want it to show rationality being a win-state not a laugh-at-me-state.
I don't think this is possible. A show with consistent interactions between the same people needs either an external enemy or internal strife to keep it interesting. Shows like Always Sunny rely on the main character's biases, stupidities, and selifshness to generate strife within the group. A rationalist house would simply not be this way. Rationalists who hate each other would find some sort of system by which they can minimize interaction along dimensions they hate (maybe scheduling separate mealtimes if one is a vegan) or simply move away. As far as external enemies go, you're creating a very different kind of show.
At the Australia online hangout; one of the topics we discussed (before I fell asleep on camera for a bunch of people) Was writing a rationality TV show as an outreach task. Of course there being more ways for this to go wrong than right I figured its worth mentioning the ideas and getting some comments.
The strategy is to have a set of regular characters who's rationality behaviour seems nuts. Effectively sometimes because it is; when taken out of context. Then to have one "blank" person who tries to join - "rationality house". and work things out. My aim was to have each episode straw man a rationality behaviour and then steelman it. Where by the end of the episode it saves the day; makes someone happy; achieves a goal - or some other <generic win-state>.
Here is a list of notes of characters from the hangout or potential topics to talk about.