I definitely agree with all the previous mentions that the tunics need to have a specific feature. TP showed with the Zora Tunic you receive there that doing more than simply palette swapping is possible. I would say that the suggestion of giving a viking feel to an ice tunic would be a bit much for Zelda, unless vikings appear in a future title. A fire tunic could be made from the hide of a dodongo, a water tunic could be like the TP tunic maybe with more of a seaweed feel to it though, an ice tunic could be designed after the white wolfos or even the yetis from TP. As for stealth, these tunics could enhance stealth abilities when worn in their respective environments, like Snake's various costumes provide different percentages of stealth in Metal Gear Solid. If that wouldn't work, I think bringing back the invisible cape (or was that a cane, too?) from LttP would would work quite well.