I have started working on a mod that changes artifacts into resources like the ones in civ games. In civs you could find things like Iron or Horses that would allow you to build new units. The only way to get these resources would be to find them and claim them, steal them by military force, or trade for them.
I plan to rename the existing artifacts in SINS and make some units and researches require them. They would mostly keep their old bonuses as well. Since it would be unbalanced to remove lots of preexisting units like Lrms. I will also be creating some new units as well.
I don't think it is possible to actually trade artifacts, but you will still be able to explore for them and steal them by military force. Hopefully when the unnamed 2nd expansion comes out this will change.
Some things that will require the new resources are final level researches, new research, new fighters, new misslecruisers, new moblie factories etc....
Hopefully this mod will increase the importance of exploring your planets, and if I can get trade working than it will make trade vastly more important and complelty change the diplomacy game.