The basic idea is once a year, update a quest or chain to have different layouts based on difficulty beyond normal; longer, more difficult challenges based on higher difficulty.

Seems straight forward enough, but in the design sense, it is more complicated.

I will use Durks as an example.
http://ddowiki.com/page/Durk%27s_Got_A_Secret
http://ddowiki.com/page/File:M_durk%...t_a_secret.png

Pretty straight forward with a fair amount of optionals and extras.

Most people speed run this for some cheap exp, favor, and a muckbane or 12.

I think on Hard, the cr's should scale like they do, but where the brothers were, should be some ambushes. The valves should be used to open the back like normal. But the furthest passage south on the map should have a shaft down leading to a second floor that has more kobolds, maybe a few more optionals, and ands witht he group near a locked gate guarded by some ogres and the brothers.

On Elite, the cr's should scale like normal, and like hard, there should be the additional floor. But this time, the gate is unlocked by the captain ogre with the guards. Beyond the gate is more tunnel to fill out the second fllor. In two rooms should be the brothers. Bound up for torture for failing to protect their lair; ogres there as well torturing them. You can free the brothers or kill them, but either way, you find out there is an ogre magi deeper that is running the show. So the final objective for completion here is to take him down.

At any rate, an example of what I am getting at. You could make the hall leading to the magi have traps players could utilize in taking him down, etc.

And I think a quest/arc per year is low cost enough to be doable.