I never would've thought of this combination of flavors, but when I came across it in 'Tastes of Italia' magazine, it certainly did seem intriguing.
Basically you skillet saute the swordfish with butter, then remove. In the pan you add 1/2 teaspoon ground cinnamon, 1/4 teaspoon ground clove, 1/3 cup apple vinegar, 3 tablespoons balsamic vinegar, S&P to taste. Simmer for about 12 minutes to reduce/thicken. Add parsley and lemon for garnish.
It wasn't so much the balsamic vinegar, really, as it was the cinnamon and clove that caught the imagination.
If anyone tries it, let me know.