| Have you tried Space Rangers 2 ? It has pretty much everything you seem to be looking for. It has a bunch of space travel, trade is one of the bigger elements, its mostly turn-based with the exception of the land battles and some black hole battles, build your own ship, forge relations with other races, etc.
The only thing is its not a big "OMG look at the graphics" game like X3 or Freelancer. The graphics are more like civilization type graphics. Great game though |