Where does the idea come from ?

It's a good question, indeed. I guess it call came up with the article from Wizards of the coast, where a comparison was made between Survival of the fittest and Tortured existence.
A deck was presented, as a possible PEZ build for Tortured existence. I'd rather say it was a proof of concept : the deck can do a lot, and may adapt itself by recursing any creature helpful in a given situation. But having only one shot of each creature is pretty tough, even with Commune with nature main-decked to find the right one (you should notice that Commune with nature is a kind of Peer through depths, creature oriented and for 1 mana less).

Anyway, the basis were there : a combo reanimator deck, an archetype missing to PEZ since heavily recursive creatures are all rare or uncommon, and are not worth a unco slot. Thanks to Tortured existence, a common enchantment with a cc of 1 black mana, every creature could be made recursive. The challenge was to find the right creatures to fill the toolbox.

A more serious build was posted by Tey Junyuan in January 2006 at cardsharks. He was the very one who posted a Tortured existence deck for Wizard, and he had visibly thought about better deck with the mechanic. Moreover, as we're going to see, Ravnica have shown up.
From five colors - unreachable in PEZ - it was now a BGw. Black as the main color, to bring in the engine and the fire power, green to fuel it all with land tutoring, Blastoderm and Nantuko vigilant, and a touch of white to play Enlightened tutor and CoP (as side... whatever...).

The build brings great additions to the deck : Evincar's Justice, a true PEZ Wrath of god, and two mechanics, both from Ravnica : Dredge and Transmute.
Dredge is precious to fill the graveyard with anything that might turn out useful. Golgari Brownscale and Stinkweed Imp both feature the ability. The imp is a recursive killer, able to block anything that doesn't have trample. The only way to get rid of it is to remove it out of the game, a feat very few PEZ card can perform (beware of Cremate and Yamabushi storm anyway...).
The big Lizard is one of the very combo of the deck : with one in hand and another one in graveyard, you can gain 2 life for every black mana you spend in Tortured existence. These 3 could be burn worst nightmare...

Transmute, embodied by the famous Dimir House Guard, is a sorcery speed way to tutor anything with a casting cost of 4 : Evincar's Justice, Nekrataal and Blastoderm, for a start. Moreover it's another way, with it regeneration activation cost, to fill up the graveyard ! And, yes, it's firepower too.

Here's the list. You may find useful to read the full article in Cardsharks, along with playtests against each PEZ gauntlet decks.

22 lands
11 Forests
9 Swamps
2 Plains

26 creatures
4 Sakura-Tribe Elder
3 Twisted Abomination
3 Stinkweed Imp
3 Golgari Brownscale
3 Dimir House Guard
3 Spore Frog
1 Nekrataal
1 Blastoderm
2 Nantuko Vigilante
3 Crypt Rats

8 spells
4 Kodama’s Reach
3 Enlightened Tutor
1 Evincar’s Justice

4 enchantments
4 Tortured Existence

Sideboard
3 Blastoderms
1 Stinkweed Imp
1 Golgari Brownscale
1 Circle of Protection: Red
1 Circle of Protection: Artifacts
2 Nantuko Vigilante
1 Crypt Rats
4 Duress
1 Spore Frog

Then, another build, called Tortured vial, was played in Paris, in February 2006. Here it is, thanks to Christophe Deslandes.

Lands
11 Swamp
7 Island
1 Seat of the Synod
1 Vault of Whispers

Creatures
4 Carrion Feeder
2 Ravenous Rats
2 Cavern Harpy
4 Chittering Rats
1 Nantuko Husk
2 Trinket Mage
1 Man-o'-War
2 Stinkweed Imp
3 Faceless Butcher
3 Ninja of the Deep Hours
3 Tortured Existence

Spells
3 AEther Vial
2 Skullclamp
2 Perplex
2 Last Gasp
2 Hymn to Tourach
2 Duress
SB: 2 Hymn to Tourach
SB: 2 Duress
SB: 2 Crypt Rats
SB: 1 Feldon's Cane
SB: 2 Golgari Brownscale
SB: 3 Annul
SB: 1 Shred Memory
SB: 2 Tormod's Crypt

As you can see, it's a totaly different build : Green has been outed to let Blue in and fully take advantage with transmute spell. White is not there at all anymore, and the five Unco are now 2 Skullclamps and 3 Aether Vial.

I do consider the Vial as a great idea : it can save mana to use it in Tortured existence activation. The most noticeable addition from blue is the Trinket mage. It can of course tutor the 5 unco artifacts, but it can also tutor the 2 artifacts lands. Unfortunately, the loss of green has a cost : no more land tutoring. Moreover, Perplex and Shred Memory are not useful for their main abilities. Perplex could be a hard counter in the early game, if it wasn't a 3 mana counter, making unplayable at the time. And when you can play it as a counter, you'd rather play it as a tutor... Not to talk about Shred Memory - as a single : remove 4 card from a graveyard is good against Threshold and Reanimator, which aren't ruling the metagame...

I thought of the deck, considering the 2 last lists, and making changes of my own.
Here how it looks.

Lands
2 Ancient Den
2 Plains
2 Tree of Tales
3 Swamp
4 Vault of Whispers
9 Forest

Creatures
1 Blastoderm
1 Faceless Butcher
2 Golgari Brownscale
2 Nantuko Vigilante
3 Crypt Rats
3 Dimir House Guard
3 Spore Frog
3 Stinkweed Imp
4 Leonin Squire
4 Sakura-Tribe Elder
4 Yavimaya elders

Other spells
2 AEther Vial
4 Tortured Existence
2 Enlightened Tutor
1 Evincar's Justice

Sideboard
1 Rune of Protection: Red
1 Rune of Protection : Artifacts
4 Duress
3 Blastoderm
2 Nantuko Vigilante
2 Golgari Brownscale
1 Crypt Rats
1 Stinkweed Imp

As you can see, White makes a big come back with 2 Enlightened tutor and 4 Leonin Squire (and 2 Rune of protection, I know). There's a lot more of actifacts land too.
This come from the Trinket Mage idea, mixed with more Dredge. As there are now 7 (or even 8 after side) dredge able creatures main deck, you should fill your graveyard up quickly. At the risk of letting go a lot of lands, or one of the Aether Vial.
Leonin squire can bring them back to your hand ! And if these precious artifacts are still in your library, the all mighty white tutor will bring them to you (although it would be quite stupid - or damn desperate - to spoil an Enlightened Tutor on an artifact land). It will still search a RoP, or a Tortured existence, indeed.

I think the deck is now way more efficient, as it mixes speed up with tools, either on creatures body or in multi-use spells.
You think different ? Please send a comment !