c_westerman13 said:
Sorry, that would help.
I was looking for something with the economic side, like the trading with all the different values for things, and the ability to eventually join one faction or other for quests.
I'll have to look at Mount and Blade, it does sound interesting.
Cheers.
EDIT: mods are always good.
Pirates! Gold and the remake Pirates live the life might be to your liking. They are, obviously, games about pirates, so you will do more pirating and privateering for whatever nation you want rather than trading, but trading is also a good way to make money.
Another game similar to those would be Pirates of the Carribean (in name only). It was originally called Seadogs(Seadocks?) 2, but got that brand slapped on it, because the movie was released around that time. It's slower with it's ship-to-ship combat than Pirates! and the melee combat is highly lethal (but also more freeform). But trading also plays a bigger role, since pirating and privateering is very dangerous if you are unprepared or piss off nations like France or Spain enough.
Another option would be Space Sims, like Elite, Wincommander

rivateer and the X-series like X3: Terran conflict, if you're into sci-fi.
There's also a ton of indie Space Sims out there,
here's a list and a website
Another possibility would be the Patrician or The Guild series. I don't know much about them, since I haven't played them. You would have to dig around a bit to find out if they are any good and to your liking.
From what I know, they are more general medieval economic/political simulations. Probably the most complex of the lot, but also with the most depth.
And that's all I've got.