Companies tend to make games on SciFi/Fantasy shows but really dont look too much into games from books unless some company makes a movie out of them.
I sometimes wonder why since there are lots of stories with a wealth of background material and even some books with a good following of readers in which some are gamers too .

There are two series which I believe can make a very good strategy game. They have a wealth of background information and the setting is perfect for a X4 game. Though I really havent thought about how to set them up, but I'm wondering what people think about a game based on the series.

1.
Author: Lois McMaster Bujold
Series: The Vorkosigan Saga

Races: Humans and Genetics: people genetically engineered for a specific purpose.
Government: Monarchies to various types of Democracies.
Most governments are limited to single solar system with the occasional interstellar empire.
Space travel: Wormholes

For further background:
Wiki Link
Didnt want to retype all the information

This universe is already setup with a variety of cultures and governments. There are a core series of worlds and many wormholes not yet explored. Lots of options to explore and expand to new worlds and the occasional conquering of a planet.

2.
Author: Hiroyuki Morioka
Series: Seikai no Monsho and Seikai no Senki or Crest of the Stars and Banners of the Stars
Races: Humans and one genetically engineered race, the Abh.
Government: 5 interstellar nations, 4 democratic and 1 monarchy.
Space travel: Planer space

For further background:
The Abh Nation fan site, lots of info

Now this one, I'm just drooling waiting for an X4 game. In this universe, the 5 nations comprise the entire Galaxy (It looks like it too me that is). Space combat is done with Fleets of ships instead of a squadron of them, you might say I'm kinda tired of playing X4 games where an interstellar empire sends out 10 to 20 ships to fight instead of thousands. With the various types of ships and the different combat arena - normal space versus planer space, there can be a rich variety of tactics and strategy.

I kinda got tired of just waiting to see if any company is planning on a X4 games on these two and looking too see what others think. Also, I know the Crest of the Stars and Banner of the Stars have been made into anime and I think there is a game out for it, but its not a X4 so to all intents and purposes, pointless