I've actually used twin Rapid Fire Transphasic Torpedo Launchers (Breen series loot). It doesn't have the spike damage of a good quantum volley, but it's steady and consistent hull damage and with the right DOffs you can keep on firing with almost no pause!

Check it out sometime.

I found that to get the most out of twin rapid fire launchers... put them in the front. Their cooldown is too fast to effectively use on a cruiser in a front/back configuration.

(Though mind you, I prefer quantums for PvE since computer opponents aren't nearly as good at keeping their shields up.)