This is a build I've been working on:

https://pastebin.com/wdv9wyzT

Basically I wanted to make use of Melding of the Flesh. Since Agnerod South gives 5% Maximum Lightning Resistance, I thought it would be fun to build something around this.

As such, we have:

Agnerod of the South (5%)

Purity of Lightning (5%)

Prismatic Skin (2%)

Helmet (2%)

Then we need 1 more % from somewhere. I decided to just go with Breathstealer and throw in Soul of Steel for the last 1%.

This makes it so all your elemental resistances are 90%.

I'm using Purity of Elements for the immunity to elemental ailments and to counteract Melding of the Flesh's -75% Elemental Resistance.

One Aura goes into Essence Worm and the other one goes into Divine Blessing Support (most likely level 21 Purity of Lightning).

We have 50% MoM and 1k Regen from The Agnostic. With a little less than 4k life, you should feel pretty Tanky.

The new Mark on Hit Support will feel very nice, since it doesn't need to be linked to a skill to work. For this, I chose Assassin's Mark.

For the extra bling, a Watcher's Eye with Chaos Resistance when using Purity of Elements and maybe Physical Taken As Lightning when using Purity of Lightning. Also, Militant Faith with Dominous is really good. Since we don't reserve mana, Clear Mind is very Pog.

This build is still not maxed out.

-edit-

Patch notes was updated with: Added - Essence Worm's "Socketed Gems have no Reservation" modifier now also causes your Blessing Skills to be disabled. This change affects existing items.

Well, shit. Gonna have to figure something else out.

Replacing Atziri's Foible with Aul's Uprising (Purity of Lightning) solves the issue. Lose a bit of damage, gain a bit of HP. Lose some Regen as well. Also, even the Purity of Lightning is expensive (around 1 EX).