http://store.steampowered.com/app/2820/
X3: Terran Conflict, give it a try.
It is a singleplayer though, but at least it lets you build your space mega-corp, a fleet of space cruisers, and so forth
Its pretty much what it says on the box too :
Build, Think, Fight, and Trade.
...although the Think bit is kind of under rated and falls onto the Trade mechanics even more.
Also, people have compared it with EVE Online, but Offline if that's any indication.
ALSO! NORMANDY SR 1 AND SR2!!! (Mod packs - look for Cadius' Xtra ship pack, its labeled as the Longsword series).