pretty much it would be a plugin that replaces one class of armor with a "spartan suit" from Halo if you are wearing diamond armor for instance all damage done to you removes hitpoints from the armor, these hitpoints are based on how many redstone or any other item you have in your inv or you could have another feature that has a time based armor regen, so you armor will default to 100% as long as you have not recieved damage for X amount of time so you get hit once you go from 64 to 63 redstone etc, once you have 0 redstone you start losing your health with each hit
I really like this. It would give a use to RSD. Perhaps make the rate of loss a bit higher, though? I can just see someone with a few stacks of RSD destroying everyone.