We recently got a new map by 5t3v3 which could be used for it:

What do you think about doing it like that:
-Link the two exits with the two unused cave entrances on map 7 (eastern desert).
-Put a whole lot of snakes in there and maybe some other aggressive monsters
-Put a few immobile monsters in there that don't attack but drop something rare. This will force people to move around in the dungeon and not just camp somewhere.
-Maybe put a hyper-tough boss monster in there when we get an appropriate new sprite (candidate: The new monster by rafael):
