Well ...first of all remember to hold block when you use the aoe skills, it will drain your stamina more faster but it will also give you a huge survival.

Now for the skills you mention, shadow cloak its a good option, nightblades receive a nice armor/spell resistance when they come out of stealh/invi ...so using shadow will give you the protection rate of a heavy armor user even if you ar using light/medium.

Volcanic rune from the mage guild : this is a good option for your aoe rotation, since it works great when combined with aoe skills like steel tornado or impulse.

I made a NB tank and here is what I found out:
Siphoning Strikes is your primary power. For group tanking it is better to choose the morph without healing (got me confused first too. you got the healer for that and need the stamina/magica more then that bit of healing it provides).
For solo the one with healing is better.

Blur - should be choosen over skills like Imoveable. Armor is affected by caps (and tanks already wear heavy). Dodging/Miss Chance is not.
Only use both if you really need the survivability.

The lifesteal dot is invaluable. Consider the morph that boost healing recevied (adds to the bonus from heavy armor).

The big weakpoint of the NB tanking is the AoE part. It is the only class without a decent AoE skill to keep aggro on mob groups.
I was told Path of Darkness is the better AoE skill for NB tanks, but had no ability to check that back yet.

Also, get a buff/debuff tracker addon.
It is important for proper resource management as healer and Tank alike.

Thanks for the all the ideas guys. The block point is very helpful, I forget. I look forward to trying out Sap Essence when I get there. Does that morph eliminate the damage component of Drain Power.

Final follow up question:
Any thoughts on the usefulness of Blur->Mirage vs. Spark->Ember Explosion.

Thanks again