Javascap

Well, there is the Clayhurst University over at the LEX, but it is sadly limited and apparently abandoned. It is, on the bright side, modular.

Updated the OP with a new map and information.

That was a concern of mine, until I conducted an experiment. So it happens, lots still hold their stats, even if you don't have the plugin. Observe. Below, I have built a nuclear power plant. Now, I quit the game, and remove the power plant from my plugins. So I fire the game back up, and... big surprise, brown box, missing plugin. But the electricity is still there! So if I make a neighboring city... I can still buy the power... And build a city from the "ghost" of a nuclear power plant that does not exist on my computer! (Bigger images here: https://s1212.photobucket.com/albums/cc447/Javascap/SC4/) Basically, even if you don't have the neighbor's plugins, you can still interact with their cities. You can still buy and sell power, water, and garbage, your Sims can still travel across the border to jobs in cities you never touched. Now, I do agree that co-op players should have some essential plugins: I don't see a regional RHW network operating unless everyone has the plugin, but plugins in other cities will not affect you, so long as you don't play other people's cities. You would develop in your own brown-box free city, building with the ghosts of other cities that develop without your input. The big point, addressing Iowndiscti's concern, is that you don't play your neighbor's cities. The only cities you touch are your own. Updating would be simple: I would have the original map with the original file names, and the participants would email me their region save. I would copy the files for their city into my computer, and the files for every other participant, then send a copy of the updated region to the participating mayors. That is how the multiplayer would work. Who's in?

Updated the original post with more information.

I would like to play a co-op game of Sim City 4 with a few willing players. If you want to join, send me a PM with *An email address you are willing to share with others. *What 2*2 area you would like to build your city on. *What you would like the name of your city to be. If someone else has claimed the same name or the area before you, you will have to choose another. I look forward to playing with you! Here is the gist of how it would work. You would develop your area on your computer as you want to. At the same time, other people would be playing on their cities on their own computers. On occasion, you, and the other players, would email me a copy of your region folder, which I would integrate into the "full" map, and send a copy of the updated map to the participating players. Through this communication, you would, in essence, be playing with a region developing without your input. This is the most recent map. Current population: 0 If you would like to join me, send a private message, and I will provide you with more detail.

Image says my entire opinion on it.