Hmm,
This is incredibly awesome.
It's really nothing like DF, and unless you want to show all the things happening in real time, I don't think the time it takes is that crucial. If you are using it to generate a fantasy city map, based on economy, for use--for instance--in a video game or rpg (obviously the user of the final map probably has to spend some art time making it appropriate looking for their game--but it's a base, of a realistic city, based on the need of it's original inhabitants and it's immediate environment), then it's totally different from DF.

Personally I'd be very interested in seeing something like that. Especially something that iterated over time, so you can input, say, "100 colonists, wealthy, very religious" for your people, and for your starting environment, "Harbor, forest within 2 km, temperate climate", "1000 years later, no major wars or invasions".

Then from humble roots, you'd have an actual, working city. Obviously you'd need some random factors (people dying, philosophies that can be interjected, such as "planned city" vs "organic growth") but it would make for a wild program.