Hobo Elf
Arcane
Found a neat little combo with shammy (can easily apply to other classes i bet) - get a Cracked Lodestone in your weapon, put Lightning Nova on a hotkey. Now go to a mob and just hold your Savagery hotkey, the press and hold Nova one. Your character will alternate using Savagery and casting Nova in quick succession, with all them shammy's lightning buffs Nova hurts quite a bit, so it's good even on 1 target. AoE packs are delt with in seconds.
How does it work? Is it a DoT that spreads around the mobs like Bloody Pox or more like Sigil of Consumption? Seems good though, I'll have to try it out.
As I mentioned the best vit/chaos based caster I found to pair with occultist is Nightblade, as their Phantasmal Blades line pumps up vit damage a lot (and is crazy good).
Another possible option is going Arcanist and getting the chaos/vit transformer of Albrecht's Aether Ray. It won't really work as a build until you hit lvl 50, but when you do it's very powerful. Arcanist can also let you focus more on Occultist as their low level stuff is good for boosting magic damage in general.
Phantasmal Blades might be my best bet for having a reliable Vitality nuke skill to go with the DoTs and AoEs although I wanted to try and make a character with a pure caster flavor. Not a fan of AAR and the investment is too deep. I hate builds that only begin to come around late, late into the game.