I think a really neat class idea would be d6 full bab no spellcasting, not lots of bonuses most of the time, but as it becomes damaged it gains bonuses (morale) to all its attributes save con. As it grows in levels it gains the benefit of spells that stack at various levels of damage that they are automatically under the effects of. Just nothing that ever increases hp in any way. Just an idea.
bump
I think it might be beneficial to get a write up on this before anyone can really comment.