Belated welcome
@gerbilOFdoom !
Your interest is shared by plenty of us - have you checked out the DynamicCities module? There is some existing market simulation that could be expanded into other types of simulation, including effecting the growth of the city more. Could also involve setting up trade routes with other cities, founding new cities, and certainly managing farms and such
One of our Google Summer of Code projects introduces a new entity scope to help simulation just like this. You can
read an intro for the project and go through
the rather sizable forum thread