See if you can get a copy of "Path of the Sword" by Fantasy Flight. They have a section for 'Schools of Combat', which are fighting styles that you learn as your character advances (you spent some time in training and a small amount of xp to learn various maneuvers). I'm almost positive there's at least one school appropriate for your style of character.
I think most people are assuming you are wanting to go with an Errol Flynn, Three Musketeers-style of fighter (this is what most people see when they contemplate the 'dextrous rapier-wielder' archetype). If this is the case, I suggest renting a bunch of the old classic swashbuckler films and watching them to pick up things you like. Then talk to your DM about your ideas and how you can make it work in game. Do you like the idea of fighting with whatever's lying around? Then your DM will have to come up with rules for dual-wielding a rapier and a baguette. Want to do lots of acrobatics and swinging from chandeliers? Review the Tumble rules (I also think that Path of the Sword has a section on flashy combat moves like this).
Another possible approach could be to play your fighter as one who is obsessed with precision in combat. He disdains the greatsword-swinging brute, in favor of placing the point of his sword just so ("I have punctured your appendix, scum. Enjoy your lingering death.") A lot of this style could be played by simply the way you describe combat. It's not "I attack the orc," it's "I attempt to pierce the orc's liver." Since D&D doesn't use hit locations, you lose a little bit of the flavor, but there are rules for damage to specific areas. You could also use combat maneuvers like Trip and Disarm (picking up appropriate feats as you go).
The suggestion of one or two levels of rogue is a good one. It doesn't mean you have to be thief-like, or even sneaky. Put your skill points in Bluff and Tumble. The sneak attack doesn't have to be a backstab or low blow; you trip your opponent, then strike while they're down, doing your sneak attack damage to represent you carving your initials into their left ventricle.
Now, if you want a really flashy, showy fighter, how about one or two levels of bard? You get a lot of the same useful skills, plus a tiny bit of magic (0-level spells like Prestidigitation, Mage Hand, and Dancing LIghts add panache, and Mending makes sure you look good both before and after the fight). Take "sword-dancing" as your Perform skill, and wow your enemies even as you slaughter them!