I like this set:
Metal Burst-great for shooting damage back at the opposition
Taunt-great tanking move and works great with Metal Burst
Earthquake/Stone Edge/Iron Head-just an attack when/if you need it. I prefer EQ over the STAB moves personally, because Stone Edge has low PP and unreliable accuracy and Bastiodon is meant to last a long time (just keep it away from Fighting, Ground, and Water attacks) and Iron Head doesn't have good coverage.
Multi-battle partner (Gen 5)-
Annoyer-I recently thought of this set and plan to try it out myself. Theoretically it could work.
Protect/Metal Burst/Iron Defense