Nope. I'm pretty sure the 11th badge is not implemented. (Until the last update or two, you were actually scored out of 15 badges, I think.)
And I totally agree on Cheeky. I can't even remember the last time I didn't get that medal in a dungeon, it's just a basic part of optimal play. (Even on purist runs.) I mean, yeah, to a large extent that's a skill thing, but on the other hand Warmonger, Miser, Hoarder, and Faithless all require deliberately limiting yourself, as does Purist obviously, and Feeling Parched is (for me at least) more a sign that I curb stomped the dungeon than it is something I've ever had to deliberately seek out (I'm still in the habit of saving all my potions for bosses, and if I don't need them for the boss...). "Kill the boss before you hit level 7" or whatever it used to be was much more impressive, IMO, although admittedly that'd be impossible to get in the Tower or Naga City (and extremely, obtusely difficult in any of the other vicious dungeons).
"Kill a level 10 monster at level 6 or lower" or maybe "kill any monster 5+ levels higher than you" would both be decent alternatives. Ding Max and Unstoppable are kind of underwhelming, but it's not such a bad thing to have a few easy-ish achievements.