> It is also a figurative goldmine for economics researchers, who get to study every transaction in an economy for once, with full information on how the funds are following.

If you're interested in that than you should look at the economy for Eve Online. It's definitely the closest thing ever created to a real economy which astounding amounts of information available to study. I'll provide some links that talk about Eve's market from economic standpoints, but these really only scratch the surface of what type of analysis is possible.

[NOTE: I am not an author of any of these posts, and I claim no ownership over them]

http://justinandrewjohnson.com/gaming/eve-online-best-game-e...

http://justinandrewjohnson.com/gaming/The-EVE-Online-Monopol...