I'm quite sure this could be achieved through a mod. --- Perhaps "sure" is a bit highly esteemed?
The dynamic economy shouldn't be that difficult, with ups and downs. And a banking system could include interest on savings, as well as bonds etc. one could buy and sell. Why, we could even have some inflation.
But basically, the economy doesn't need to be that difficult: certain areas produce certain goods, others produce other goods, so it's just a matter of buying something here, like wine or a special renowned sword, transport it somewhere where they are in want - quite natural to get a profit out of it. Plus highway robberies, of course!












