I'm going to contribute to this one, what with my newfound competitive knowledge.
Total Edit: Ninja'd, but CB Cranidos wouldn't do so well anyway. Why? Frailty. Leave that to his a bit less frail evolution, Rampardos.
CB
Item: Choice Band
EVs: 252 Atk, 252 HP, 4 Def
Nature: Adamant
Ability: Mold Breaker/Sheer Force
-Head Smash/Stone Edge/Rock Slide
-Crunch/Brick Break
-SuperPower/Hammer Arm
-Fire Punch/Earthquake
Okay, pretty spastic set. Choice Band powers up that ridiculous attack, but keeps you using one move blah. Adamant for more power, no problem. Now here's the problem. Go with his lesser ability and have much better offensive options like SuperPower and Fire Punch, or with insane Sheer Force for just plain murder. Sheer Force also prefers Rock Slide over Stone Edge or Head Smash, and Stone Edge is usually preferred over Head Smash anyways, but 150 BP STAB is nothing to be taken lightly. If you go MB, Fire Punch is a given, and SuperPower is crazy hit-and-run power. Crunch is generally preferred with SuperPower, but Brick Break is an option for a less costly move. Hammer Arm is an option for hitting with power similar to SupwerPower, but lowers his sub-par speed. Earthquake is a Filler mostly, but can net a few blows.
I'm a bit off on the EVs I believe, but it's probably better bulky on this one... As if it can be relatively.
Rock Polish
Item: Life Orb
EVs: 252 Atk, 252 Spd, 4 HP
Nature: Jolly
Ability: Sheer Force
-Rock Polish
-Zen Headbutt
-Rock Slide
-Earthquake/Brick Break/Crunch
Set up late game, then go for a uh... 'Sweep'. It'd be easier if Rampardos wasn't so slow, but it's passable and can be used. Zen Headbutt is an oft over-looked move, but it can take a bite out of most. Don't aim for anything with Bullet Punch/Mach Punch/Vaccuum Wave/Aqua Jet Et cetera though. Rock Slide is STAB and crazy powered with Sheer Force. Last move is up to you, EQ is you want QuakEdge, Brick Break for coverage, and Crunch for Sheer Force and Shedinja.
Cranidos
Cranidos is a force to be reckoned with in LC, but it should not just be slapped on any team. It's considerably faster in-proportion to Rampardos, sharing it's base stat, but it's still quite slow. If you can manage to get a Baton Pass'd speed to it, let the good times roll, as it's 125 Base Attack is quite threatening.
All is not sunshine and rainbows though, as it's quite frail, and is taken down quickly by Priority of any kind, really, because it is sporting 67/40/30 defences. It's not Abra weak, but take caution.