I recently experimented with a dual wielding Restoration spec 0/31/40
WorldofWarcraft.com -> Info -> Classes -> Shaman -> Talent Calculator
The points put into Enhancement make Earthliving weapon add 30% more spellpower to each weapon, and makes flametounge totem add 15% more spellpower. By dual-wielding you can place the Earthliving enhancement on each weapon. This provides a HUGE boost to your spellpower, however it does not boost your single target heals as much as you would think. You lose the talent Tidal Waves:
Tidal Waves (rank 5):
You have a 100% chance after you cast Chain Heal or Riptide to lower the cast time of your next Lesser Healing Wave or Healing Wave spell by 30%. In addition, your Healing Wave gains an additional 20% of your bonus healing effects and your Lesser Healing Wave gains an additional 10% of your bonus healing effects.
This 20% loss on Healing Wave and 10% loss on Lesser Healing Wave brings our single target heals back to about where they were without the Dual-Wield. The loss of the 30% haste, and Riptide lower our “emergency healing” significantly. Losing Earth Shield, Riptide, and Tidal Waves, makes this spec not viable for 5-man Heroic healing (since you have no other healers) and 10-man raiding (Your lifesaving is NEEDED in 10-mans). HOWEVER, 25-man Heroic Raids is where this spec shines. Since there is no Tidal Waves type talent for chain heal, this spec provides a huge boost in the power of Chain Heal. In 25-man, Shaman are often assigned to raid healing because of Chain Heal, and with this spec boosting mainly Chain Heal it is AWESOME for the CH spam.
Sadly, I will not be keeping this this spec for the time being, however, as soon as i hit 25-man raiding consistently, DW Resto, Here I come!!