UPDATE 2:
It is confirmed, enhancement healing is dead.
Enhancement shamans receive a healing debuff similar to the ones Retribution paladins have had since the encounter’s initial implementation- Crygil
I mostly play as a restoration shaman in World of Warcraft. In that role I recently found an interesting alternative way of healing the General Vezax encounter in Ulduar on hard mode.
For those that do not know: This boss fight prevents players from regenerating mana through conventional means and provides an alternative source of mana in the form of Saronite Vapors. If you wish to kill the boss on hard mode, however, you may not use any of these vapors - meaning you are generally confined to your initial mana pool.
There are some exceptions to the no-mana-regeneration rule though - meant to allow certain DPS classes to function. One of the abilities that actually work is Shamanistic Rage from the enhancement tree of shamans. Improved Stormstrike works as well.
Some clever shamans therefore had the idea of speccing deep into enhancement for this encounter to be able to regenerate mana by meleeing the boss.
This does not gimp your healing output as much as you might think for this fight. You do lose Riptide and Earth Shield but actually gain healing power through the insanity that is the combination of Mental Quickness and Mental Dexterity - and the fact that you can dual wield weapons with a +heal enchant and Earthliving on them. In 10 men mode I easily hit 4000 bonus healing during combat, a value that I could never reach in my normal spec.Literally all you do in this role is stand behind the boss, autoattack, Stormstrike on every cooldown, use Shamanistic Rage once 30% of your mana is gone and then on every cooldown, and cast Greater Healing Wave on the main tank or any raidmember that has lost health (if that is your task.)
Healing Waves heal for a considerable amount (11.6k on average in my case) but be aware that you can't continuously cast these without going out of mana. At the very least you need to allow for breaks for your Stormstrikes and Shamanistic Rages. Ideally you leave some room to melee in between too so you can charge Maelstrom for instant heals (which save you cast time and therefore give you even more maelstrom procs.) Saving a full Maelstrom charge for healing during Shamanistic Rage (and Surge of Darkness if your guild doesn't kite the boss) can be very helpful.
If your other healers don't go out of mana, you should always be able to keep mana up as well. If they do, you will eventually be overtaken by the incoming damage and be forced to chain-cast heals. This will drain your mana quickly - but at that point you already lasted longer than all other healers in your group.
Gearwise I tend to go with my full normal healing gear, obviously favouring crit pieces as opposed to mp5 pieces, and a Stonerender with a healing enchant. Any one-hand or offhand weapon will do here as long as it has relevant stats such as crit, hit, ap, strength, agi, expertise or even haste. Sockets are at premium because you can socket 19 sp gems in those. Elemental shaman gear is actually very good as it usually doesn't have mp5 but has hit - which increases mana regeneration.
If you still find yourself starved for mana you may consider using a trinket with hit on it and a useful proc or use effect. Blood of the Old God and Living Flame should both be decent.
The spec leaves quite a bit of room for change. You can easily drop Improved Shields and Static Shock to gain access to Enhancing Totems for example. The melee damage you will do in full restoration gear will be minimal anyway.
I'll leave you with a report from one of our 10 men hardmode kills from World of Logs.
