oh man, i love that idea...
so maybe along the same lines as you had of "feeding the dungeon," maybe make the 'living dungeon' theme two fold and have it occaisonally 'poop' out rewards. for instance, you could have sort've random "food" pellets that when you drop them in the dungeon it spawns either a monster (a skellie, or a slime maybe) or perhaps a hero (sometimes a fighter maybe a healer or nuker-type). so players can kind of treat it as a bit of a terrarium, sprinkling the pellets in, and then watching the 'eco-system' settle itself. depending what dies, maybe that is what spawns new 'pellets' to come outta the dungeon.
that way you try to lean the tables in favor of different outcomes - maybe if more skellies survive, the dungeon is more likely to produce more 'undead' related foods, etc.