CrisGer
Gläubiger
There really aren't any fully developed ones that I know of, in the best style. It is an idea that many have discussed and there are soem games that have been altered to include a lot including Oblvion and Skyrim but neither are MMOs. The problem is that most MMOs cannot be modded due to the way that files are shared and the fact that everyone in a persistent game world has to have exactly the same files or it wont work. but it is interesting to think about. Second Life had some aspects of this. And Blue Mars might have had if it had worked.