Ok, i worked on that homecity script i wrote about a few posts ago. I fixed a bug that prevents AI player from founding cities.
And I discovered you can also access Europe screen when entering a foreign king's city.
I have now two possibilites:
a)
I can seperate Europe screen for each King city, means you would have access to 3-4 different trade cities. I think I can even attach a unique economy to each Europe screen. But I'm not sure if it's too much micro management. You would have to keep track of multiple Europe screens. Units recruiting and purchasing would only be allowed in your home city (we won't steal units from other AI, right?). Keep in mind that right now Diplomacy with foreign kings isn't possible. Foreign king would have no possibility to stop you from entering his city.
b)
I can take Ekmeks idea for making Rome the king player and only create one Europe screen city on the map (= Rome). All players would go to that city for trading.
I would try to bring in the inland sea script from Civ4, placing Rome at the middle top area.
Plan b) is much easier to implement, means lesser bugs and better AI behaviour.
What do you think about it?
EDIT:
Uploaded a first version. It works like I described in b) but without inland sea script.
Rome location is centered on map and will be revealed for all players. I also stopped Rome from doing any expansion (hopefully).
instructions:
1) install brand new Mare Nostrum Beta 002
2) install MNEuropeScriptRome
Sometimes AI player creates it's first city inland having no sea access to Rome. Stupid AI doesn't know it could use caravans to access Europe screen.

I'll try to fix that.