I'm opening this thread at the request of exodia91 following on from a discussion in New Features.
The plan is to some features to the game to enable modders to write new screens, and ultimately new cities for the PC to dominate. To this end I want to add XML interface files; the ability to add user defined graphics, buttons and screens; and Lua scripting so you can attach scripts to buttons.
For a proof of concept, I plan to do a city mod called Abby's Prospect using my steampunk interface mod as a starting point.
Abby's Prospect is a trading city which has come to attract some of the more scientific elements among the refugees that wind up stranded in Mundiga. Like Crossgate, the city has a strong criminal element, although the gangs don't rule to quite the same extent. There are civil authorities to consider, as well as the remnants of the demon worship cult that once ran the city, back in the days when it used to trade directly with Hell.
The city's scientists and inventors were first encouraged to settle here in the hopes that the well known antagonism between science and magic might help keep the cult from re-establishing itself. It's a strategy that's been successful. Up to now, that is. If the player wants to control the city, he's going to need to involve himself in a struggle between magic and science, and Heaven and Hell.
I want to stress that, at this time, this is speculative. I need to code up some new features for the game to enable all this, and until I get that done, nothing is going to happen as regards the mod itself.