If you want to play a modern Elite clone right now, try OOlite and its many useful add-ons.
One of the joys of Elite was that of instant Spaceship Captain competency. You started off with a simple ship, with simple goals and a well defined upgrade path. The flight physics were just about perfect and you could take as much or as little time you wanted to accomplish any task.
I doubt that adding multiplayer to Elite would improve it, let alone keep it the same game.