Vanilla helmets can be pretty boring sometimes. Can we have mob heads which have some armor points?
To obtain such head, you'd need to combine a helmet with a mob head. It would give you a mob head with that helmet specs. Then you could enchant the head in enchanting table for additional specs. The cost for it can be easily balanced.
I've never tried modding by myself, so I don't know if it possible. Maybe the way would be changing helmet's texture+model or smth like that.