Suggestion:

Undaunted Platinum Key/Chest for completing a dungeon with Gold requirements + no deaths. (If that isn't challenging enough, add a timer.)

Rewards?

What you want for this? PvP Gear Pieces? Tokens for choosing particular Undaunted Pieces? Something else?



With regard to mechanics, they already exist for tracking group deaths and completions times in dungeons. If you have no death (+ beat the time?) for Silver Pledge, get upgraded to a Gold Key. Do that for the Gold Pledge, get a Platinum Key. Just add a third chest at the Encalve.