Two really good ideas that came to me today.
The Star Wars - based on the limited run comic book series (soon to be trade-back) based on the original screenplay by George Lucas. Would be great because it would be self contained, plenty of room for the GM and players to take the universe in the direction they want without anyone complaining about how that's not how things happened after it ended... because there is nothing after it.
The other came while replying to another thread...
The Star Trek mirror universe. Some of the best episodes of Star Trek show the alternate universe where everyone advances through back stabbing. Outside of the few episodes and a few books there isn't much material so it leaves a lot of room for groups to do as they want. You could design the game to be played in multiple ways, either fighting against the Terran Empire or serving it or using other variations as presented in the different materials.