I discovered this item and i was intrigued, because im pretty sure this is the only headpiece in game that has any kind of elemental resistance. Does anyone know if disenchanting this helmet makes the "resist fire" effect available for other headpieces? Does anyone know of other items that have an enchantment that usually isnt "allowed" on its piece?

No, you cant add fire resistance to a hat for any reason. You can only find it added in unique loot like that helmet. There are other items with unique enchants.

No. When enchanting, you can only enchant "allowed" pieces. If you found a helmet with an "unallowed" enchantment, rejoice, but don't expect to duplicate it.

Well, I've GOT to get me THAT one, now...

Also...

darn dragon priests, they are casters, using staff and such, and have a heavy armor piece at top, meh, and better is, they cast alteration armor spells, requiring to wear no armor, wtf ? cheating very much....