), I've spun off a new addon from Ignore Race/Class Locks called Ignore Campaign/Difficulty Locks, which does more or less exactly what it says. As with its "parent" addon, this addon doesn't actually unlock anything; it just bypasses the lock checks in the character creation dialog for campaign and difficulty levels, for all your Madness-mode Infinite Dungeon needs. And the two addons should work seamlessly together, if you want to ignore lots of locks. 
(And this, of all my addon updates, I have been able to successfully upload to Steam...
)