I was wondering, wouldn't a suit of metal armor make you weaker to tempurature-based damage? Also, would it protect you from some effects of shock? Furthermore, shouldn't acid (which is what the Poison effect is, apparently) do damage to it as well as you?
Fur armor definitely should help against frost, and chitin, since it may be made from shalks, might help versus fire.
What effects would other materials have?

Something like this?

http://koti.mbnet.fi/dreamy/morrowind/plugin/downloads.php

Not really...looks nice, but I was wondering more about spell theory.

Actually, metal should PROTECT from short bursts of heat/cold, but make you more susceptible to longer-duration spells.