You have been ssadly missinformed on a number of counts - there have been various conversions, the most famous perhaps being the one in the previous SM codex, there have been Warhammer Emperors, but the 40K emperor of mankind has never been modeled by citadel

Equally, I have the zoat stat lines in my WDs somewhere, but Zoats were not orriginally tied to Tyranids, Zoats started out in Warhammer as allies to Wood Elves, then came the "Space Zoat" that went with the Eldar

 

Ouch. Thanks for the imput. They went with the eldar eh? Then wy are they under the tyranid evolutions page on GW's official website. I ask not to challenge your might, O'Supermod, mearly to carify.

Thanks:

Mordacii

 

OK its a reasonable question and I am a little rusty on the subject, but I think at one point they were considering putting the 2 together, they may have done, perhaps someone else can recall, but certainly that is where they started (I know cos I had Wood elves and 2 zoats and Yriels personal company with a space Zoat.

Don't have might, I just fake it well

 

History of Space Zoats

Zoat History
Zoats are large, centauroid creatures. There are only 8 models ever sculpted, 4 for SciFi and 3 for Fantasy. They were conceived by Bryan Ansell and sculpted by Nick Bibby. The 4 SciFi models weapons are described as (names as in Chapter Approved):
Zoats RT / WD ad 97* / WD ad 145 / WD 145
Officer (Gharg) Power Glove / Power Fist / Power Glove / Power Fist
Bolt pistol / Flamer / Flamer / Flesh Ripper
Hero (Loorg) 2 Bolters / 2 Bolt Guns/ 2 Fleshborers / 2 Flesh Rippers
Trooper (Slaarsh) Bolter / Bolt Gun / Fleshborer / Flesh Ripper
Special Weapon Heavy Bolter/Multi-Melta /Missile Launcher/Barbed Strangler
Trooper (Sheaar)

*--In the Chapter Approved version of the Eldar Pirates' Zoat Terror Squad: All the Zoats also came with Bolt Pistol, Melta Bombs, Flak Armor, Communicator, & Resperator. The squad was made up of the Hero model, 2 Trooper models, and the Special Weapon Trooper model. For +13 pts, you could substitute the Officer model for the Hero model, with the appropriate weapon substitutions.

There are several description of Zoats.
The oldest: Rules for 1st Edition – Rogue Trader, p.202 - Zoats
Zoats are the most common of Tyranid's many specially engineered slave races. Other slave races are little more than animals, mere blobs of protoplasm dedicated to cleaning and maintaining the Hive Fleets they are apart. Even hulking spacecraft which compose the Hive Fleet are in a sense races as they are grown and nurtured from a common, albeit much modified, biological stock. Spacecraft are mindless monstrosities and the vast majority of other slaves are so dedicated t a single purpose it would be inappropriate to think of them as creatures. Zoats, on the other hand, are completely independent living creatures much like their masters.
The Xenobiologers of the Administratum believe Zoats were created purely for combat. Tyranids, being creatures of space, suffer discomfort if they spend too long on a planet. Zoats, however, are stocky animals that feel quite at home in a variety of atmospheric and gravitational condition. Like Tyranids, Zoats are centauroid. Their two rear sets of limbs and are heavily built providing the creatures with its means of locomotion. The front limbs are manipulative organs of great strength and are used to wield a variety of weapons. Unlike Tyranids, Zoats will eat anything though they are largely subsist on a daily diet of three reconstituted protein based woven biscuits called Zoatibix. Zoats are common Hive Fleet inhabitants, often equaling the number of Tyranids themselves.
Although Zoats are a slave race, Zoats occupy important positions throughout the Hive Fleets and individual Zoats can gain great power. Rebellion from Tyranid control is not unknown, but is extremely rare. This is because Tyranids secrete a special slave-hormone which suppresses the Zoats' natural sense of independence. However, broken away from the Hive Fleets or have become lost during scouting or exploration missions. Without the inhibiting influence of Tyranids slave-hormone, Zoats are able to develop strong psychic powers. The path of independents Zoat civilization is incredibly diverse, with small groups isolated from each other on widely scattered planets.
Trooper: M7,WS5,BS3,S4,T5,W3,I5,A2,LD10,Int9,Cl9,WP9
Champion: M7,WS6,BS4,S5,T5,W3,I6,A2,LD10,Int9,Cl9,WP9
Hero: M7,WS7,BS5,S5,T6,W4,I7,A3,LD10,Int10,Cl10,WP10
Mighty Hero: M7,WS8,BS6,S5,T6,W5,I8,A4,LD10,Int10,Cl10,WP10
Zoats of the Hive fleet are never psychic. Independent Zoats are too diverse to include here in any detail, but a typical population might result in personalities having a 50% chance of psychic powers. Some populations are more psychic than others.
Organization. Zoats fight in military units of four. Their unit leaders are Zoats, although higher ranks and more technical positions are likely to be filled by Tyranids. Any Tryanids force must have at least half its numbers made up by Zoats.
Equipment. Zoats use standard Tyranid equipment. Zoat units and leaders can be equipped using the same charts as Tyranids.
Typical Squad. A typical squad comprises four individuals including 1 leader and, usually, 1 special weapon warrior. Clothing takes the form of a harness providing holster positions for various weapons. The basic weapon carried is a bolter, the special weapon is a heavy bolter. The officer also has a bolt pistol. This is exactly as for Tyranids.
Uniforms. Zoats wear the same harness as Tyranids
Weapon Generation. Generate weapons and equipment using the Tyranid charts.
Transports. Generate vehicles using the Tyranid charts.
Tactics. Zoats form the warrior-corps of the Hive Fleets and are found in the capacity of guards and police as well as fighting warriors. They are extremely potent fighters and fit well into the Tyranid ethos of the fast, hard strike.

The 2nd: Rules for Eldar Pirate armies – Chapter Approved, p.103
The Eldar Pirate may have 0-2 Zoat Terror Squads
Warriors: M7,WS5,BS3,S4,T5,W3,I5,A2,LD10,Int9,Cl9,WP9
Champion: M7,WS6,BS4,S5,T5,W3,I6,A2,LD10,Int9,Cl9,WP9
Basic Equipment (all models): Flak Armor, Communicator, & Respirator
Squad: 2 Warriors with Bolt Pistol, Bolt Gun, and Melta Bomb Grenades
1 Warrior with Bolt Pistol, MultiMelta with Targeter, and 4 Suspensors
1 Leader with Bolt Pistol, 2 Bolt Guns, and Melta Bomb Grenades
PV = 341 / Squad
Optional Zoat Squad Upgrade:Upgrade Leader by Substituting a Power Glove and Flamer for the 2 Bolt Guns for +13 pts per squad.

3rd: Rules for 1st Edition, Version B – White Dwarf 145, WD43 where they changed from mere muscle to highly intelligent.
Zoats share the six-limbed structure of Tyranid Warriors and are probably an ancient and highly evolved form of bio-construct created using Tyranid's own genetic material. Zoats were created as investigators, their main role being to understand and communicate with creatures outside the hive mind, assessing their value. Zoats are capable of assimilating information about languages and psychology with stunning speed, making rapid and accurate leaps in their comprehension of alien creatures. Due to this innate capability of understanding the subtlest nuances of facial and body language, Zoats are remarkably charismatic and enigmatic creatures who are able to convey more meaning in a look or gesture than a native can manage in a sentence.
Zoats are often used to subvert members of alien races to bring them under the control of the hivemind, leading them against those who try to resist the Tyranids. In keeping with this role Zoats are tremendously strong warriors with thick, horny hides, Driven forward by their four powerful legs, a charging Zoat is like a battering ram of hide and muscle - such that sheer speed and momentum keep it moving even if mortally wounded. In hand to hand combat a Zoat can crush most opponents in seconds - living proof to other races of the awesome power of the Tyranids.
0 to any number of Zoats at 50 points per Zoat
M6,WS5,BS3,S6,T6,W3,I5,A2,Ld/Cl9
No armour, Save: None, Move: 6�
Weapons:2 Flesh ripper pistols or a Flesh Ripper pistol & a Power Fist or a Strangler
Notes:Each Zoat allows you to include one band of Brood Brothers in your army. A Zoat armed with 2 pistols may fire both of them in the same turn with no penalty.

Rules for EPIC scale battles
EPIC STATS Speed/Range/Fire Power/Assault/Armor/Wounds/Special
Zoat 15cm /25cm /2 /4 /5+ /1

Various people have written their own rules for 2nd Ed, 3rd Ed, Space Crusade/Star Quest, and for Space Hulk. Some use the "fantasy" zoat that carries the "orb" to represent a jammer for the hive mind for Zoats who are not part of the Tyranid army. There are even rules for jamming the hive mind by getting the Zoats drunk.

 

I second all the info by davidporter on 40K Zoats. One further bit, the "Zoat" may have transformed, according to GW fluff, into the Zoanthrope, so, you will see people refer to Zoanthropes as Zoats.