I mentioned this a while ago. I think you could make a set of rings(maybe even include an ammy) that is very rare and is a compliment to different builds. You could have a version for pew pews, melee, casters, and summoners. This would make putting the appropriate set together a difficult task and could be yet another bridge in the gap between top players and mid level farmers in the trading market.
Edit: It would be kind of cool if you could make a set of rings that could add a synergy effect to the class specific sets or had a strong bonus that only took effect at a higher character level.