I actually think I'm going to (gasp) go straight Swashbuckler, at least to start. Especially if you'll let me use the
WotC "Dead Levels" level 4 ability for Swashbucklers.
The character will be
Maria de la Rosa Almeda y Carazo (known only as Rosa or Rose on Coral Island), a passionate beauty with a sharp blade and sharper tongue. A thrill-seeker and risk-taker, Rosa rarely if ever backs down from a challenge and takes insults from no one. She never speaks of how she wound up on Coral Island, but careful observation will reveal that her sword is exceptionally high quality and Rosa unconciously carries herself with an air of nobility.
Mechanically, she'll be a fencer focused on Combat Expertise combined with Deadly Defense (fight defensively or take at least a -2 penalty with Combat Expertise to get +1d6 damage on all attacks for the round, from Complete Scoundrel) to deal damage while (hopefully) taking little herself. She'll fight with rapier and dagger, but the dagger is only for show; there's not enough feats to take the Two-Weapon Fighting chain with her. Her rapier,
Flicker, is an item familiar heirloom. If you end up deciding to use firearms, she'd have a pistol; otherwise, several daggers are hidden on her person in addition to the obvious one on her belt.