The foul depths of the Quality Well
Solution 1:
Nope - just a secret joke dungeon. Rumor has it that if you're particularly unfortunate, you might stumble across Development Hell, as well.. (I know you mentioned it, but seriously. Development Hell. It deserves a second mention.)
Oh, and you might also find Bashiok lurking around the Oasis in Act 2. If you've got Rakanishu's Blade, he's even worth an achievement.