Okay when it comes to PvP the last thing I would expect to see is an Elementalist using a hammer. However yesterday a saw just that.... and then got killed by it....... Anyway this is the build this daring ele used.
Earth Magic 10+1+1 -12
Hammer Mastery 12 -12
Energy Storage 8+1 -9
Earth Shaker
Crushing Blow
Staggering Blow
Mighty Blow/Aura of Restoration/Earth Attunement
Stoning
Armor of Earth
Kinetic Armor
Ressurection Signet/Aura of Restoration/Earth Attunement
Essentially you would start by casting Aura of restoration and/or Earth Attunement if you brought them. Then before attacking casting Armor of Earth. After building up adrenaline start by using Staggering Blow followed by Kinetic Armor then cast stoning when ever possible. And of course using crushing blow after stoning and Earth Shaker whenever you can. At 12 hammer mastery Staggering Blow would cause 13 seconds of weakness unless you have a 33% longer weakness haft. So you would beable to get out two Stonings. Of course if you can pull this off in a chain the enemy isnt going to be around to long.
Staggering Blow->Stoning->Crushing Blow->Stoning->Earth Shaker
That chain would be very painfull and annoying to casters. Considering they wouldnt have time to run or cast spells.
I would say the main flaw in this build is that if your Armor of Earth wears out and you forget to re-cast it you could get pummeled to death by warriors.
E/W Hammer Warrior
Enraged Soul
LightningHell
What if your target kites? Armor of Earth makes you slower. I would suggest switching out Kinetic for Aftershock (and IMO Backbreaker for Earth Shaker, not that I play Warrior, but I get owned by Backbreaker. Earth Shaker + Aftershock would be nice, though
) In any other circumstance other than Arenas, however, I think you would deal a lot less damage than a common Warrior, for example. Not having 16 in a Weapon attribute hurts. (At least, those Melee R/W couldn't kill me!)

Sirkaze
I was a E/W and i used hammers when i first started the game it was fun and quite good but im a ele/monk now :P
Scourgey
I have an earth ele, he does very well in TA arenas if you got a good protection monk.
It's
Hammer 12
earth 16
energy 4
Backbreaker (e)
crushing blow,
aftershock,
irresistable blow,
mighty blow/hammer bash (switchable depending on what you like)
frenzy/flurry,
Obsidan flame,
Ressurection Signet.
Yes, it's a very risky build. If you encounter runners that are almost dead, use obsidan flame to finish them off.
backbreaker->crushing blow->aftershock->hammer bash->irresistable blow will pretty much kill any pvp monk if they don't have any enchants or cross healing.
Use Frenzy or flurry to build up adrenaline and if frenzy, use with backbreaker to do extra hits, although it's possible to do crushing blow + aftershock without an attack speed boost.
If you encounter kiters, just switch targets or use flame on someone. This build does really need a snarer to build up adrenaline
It's
Hammer 12
earth 16
energy 4
Backbreaker (e)
crushing blow,
aftershock,
irresistable blow,
mighty blow/hammer bash (switchable depending on what you like)
frenzy/flurry,
Obsidan flame,
Ressurection Signet.
Yes, it's a very risky build. If you encounter runners that are almost dead, use obsidan flame to finish them off.
backbreaker->crushing blow->aftershock->hammer bash->irresistable blow will pretty much kill any pvp monk if they don't have any enchants or cross healing.
Use Frenzy or flurry to build up adrenaline and if frenzy, use with backbreaker to do extra hits, although it's possible to do crushing blow + aftershock without an attack speed boost.
If you encounter kiters, just switch targets or use flame on someone. This build does really need a snarer to build up adrenaline