Well... time for a SUGGESTION (yeah, I know... no suggestions... but this one is not for the game itself... well... a little...).
To the In Demand part of campaign, Lab 0 already said about the end of all the hight tiers. I suggest not rid at last one of then, if no one gets at end of the campaign: the $20.000.
With this tier, a backer can create a secret room (not only a secret room...), a monster, a boss and an incarnation. Check.
To allow this still working in the In Demand, we only need change a part: besides a room, the backer will create a mini-dungeon!! And all others (monster, Boss and the first glimpse of the incarnation) needs to appear here. With this, Lab 0 can work in the game and only work in this dungeon after all are done, applying this one as a DLC after.
The "Secret Room" tier can be change to some like this; a room who entrance surges only after a DLC (or after get an item only obtainable after a DLC)
(we can try make something like this to others tiers - Monsters or Bosses - but can be more hard to do, or confine this ones in a little space or no relevance...)
What you think about, guys?
EDIT: A New Monster can be setted to be respawn in some or random places after get an item only available by DLC. A Boss can be make at same way (spawn in a place after get a item) or can be a random roaming boss. Well.. in any case, this need be pointed in the tier (the existence of some restrictions).