Would it be possible to create a "for the challenge only" mode that gets algorithmically harder depending on the setting?
It would be similar to reaper I imagine, but rather than only having ten possible skulls, it would have 999 skulls and for each skull, mobs would get 50 more prr/mrr/spell power/melee power/ranged and +3 to saves/DCs/stats/skills. Healing anyone including yourself is penalized by 1/(1+0.25*skull). You can only enter a quest on this mode if you are at the quest level or below (not the +4 leeway thing reaper allows).
There would be NO BONUS or BENEFIT to doing this mode other than bragging rights. Allow the use of Reaper points in the mode but don't have it grant reaper XP or named loot AT ALL.
Instead of XP, this mode could just put you on a leaderboard somewhere that says "this guy did "Haverdasher" on 'Crippling Insanity Mode: 25' in 4 hours, 14 minutes, and 52 seconds".
This website might only remember the three quests you did the highest level modes on with raids given special consideration.
Those who stand out would be put in newsletters and have their builds published on the forums.
I want to see what the highest numbers players can get are, and what exploit builds accomplish them.
Who's with me?
P.S. One more time for clarification, THERE SHOULD BE NO BENEFIT TO PLAYING THIS MODE BEYOND BRAGGING RIGHTS.
If devs think it's too much work for something so stupid, create this challenge mode for only one dungeon and see how many people play it. If it becomes popular then create it for more dungeons.