Not sure if it's ever been done, but why not a DF themed RtD?
Like, you start in a small little Human hamlet, you get some adventurers together, they adventure, and pretty soon you come across a giant abandoned fortress filled with loot, traps, and death. Classic in that each member faces mostly the same threats, and linear progression is possible.
Next idea of mine was Drone Combat.
This is one that I took from the ashes of my original project, Everlasting Mecha War. It's basically a watered down version where drones, not suits, fight. There's a parts bank and everything. Each "core" has the stats, and generators/weapons give specific stats and roll mods. Each player got one drone and an account, where their cash totals were kept (In a reserved-post list, maybe?) along with any spare parts they didn't want to chunk. Also comes with a "shop" post.) I do intend on launching this next month when school cuts out.
Another one was Existential Nightmare Room- like a half suggestion half RtD hybrid.
Six players are locked in a big, empty room. You don't know anything about it. You know there are things here, but what are they?
Players start by thinking of- what they're wearing, what two things they're carrying, and one object in their IMMEDIATE vicinity. These autosucceed.
After that, players describe objects.
Rolls:
1- Horrible failure capable of creating monsters the human brain cannot even comprehend. While this is lessened at the start, it can get very Lovecraftian in here.
2- Lesser Failure. The object dosen't come out the way you wanted it, it's cursed/evil, or something. It may try to kill you but it won't be super deadly.
3- General Failure- The object comes out mostly the way you imagined it, but it's evil, alive, and (not that) dangerous.
4- Meager Success- The object may lack some of the detail or power of the described object.
5- Total Success- Pretty much anything that won't break the game.
6- Overkill- Overdoing it. Such as conjuring a metal table- this one transforms and has death lasers. These rolls net mostly 2s, but the objects can always be awesome enough to become a 1.
Note that there might be some non-player activity, as in, "Random object has appeared" based on whatever people vote for the most for one day/turn.
It's a self-fueled magic dungeon!