Quote Originally Posted by cfalcon View Post
So if a rogue wants to dual wield he just gets that sort of as extra damage, and if he takes the feat he gets to wield a bigger weapon in the main hand and gets +1 AC.
Yes. Although you might choose to attack another creature with your off hand weapon or use the attack to apply your Sneak Attack, if you missed the first one.

Are real world weapons styles such as "a case of rapiers" (two one-handed weapons in 3.X lingo) supported at all?
As was mentioned, yes. Take that feat.