So after some thinking on how you can really use some of the special forge world vehicles, namely the Atlas, as well as the Trojan, I have thought of an army idea that can be quite good and exceptionally durable. I call this the Armored Repair Shop because it centers around leman russes and techpriests with Atlas and Torjan support for lots of repair and support abilities. With their abilities you can repair a lot of damage to your leman russes and keep them in the fight far longer, also if you have no need to repair then techpriests can throw out PoTMS for giggles.
To recap for people who did not read my run down of the Atlas & Trojan its pretty simple. The Atlas can tow a vehicle but can also provide rerolls to a techpriests repair rolls as well as give an additional free one if they are within 6" of each other. The Trojan is a DT for techpriests plus gives out preferred enemy to one tank a turn if within 6". Here the Trojan isn't an integral part but is useful for your techpriests if you need to move them around.
The army is going to be built around three techpriests and three servitors, that are going to form one unit, this gives you a 2+ to pass a repair roll, which is rerolling from the Atlas, which each gets to do twice so you have 6 almost guaranteed repairs a turn. That's pretty awesome if you ask me, plus its minimal in pts.
3x Techpriets - 120pts
3x Servitors - 30pts
Atlas - 85pts
All of that is 235, and if you want to throw in the Trojan for transport its a measly 35pts more.
The next part of the army is your russes. Here is where I would go, I'm taking the Steel Host, thats 3 Russ squadrons, a tank commander squadron, and a hydra. The hydra is extra but thats ok, its relatively cheap and its the special rule for the steel host that I want, since I'm taking leman russes any way, they get preferred enemy if they are within 12" of the tank commander.
My direction for this army is executioners. With preferred enemy to reroll those ones for gets hot, and with 6 repair rolls with your techpriests, you can ensure these guys do little to no damage to themselves from their gets hot weapons. I would upgrade each to have a lascannon, and if you want to spend the points, the plasma cannon sponsons are not bad here as you have a lot to help you save gets hot damage that you usually lack.
Basic list
Tank commander executioner w/Lascannon-195
executioner w/las-165pts
squadron 1- executioner w/las-165pts
squadron 2- executioner w/las-165pts
squadron 3- executioner w/las-165pts
Hydra-70pts
Thats all 925 pts, add the 235 from above and you have still plenty of room for the rest of the army. You could go with another tank commander, but honestly a CCS in a transport will do fine, or you could go with yarrick for your CAD Hq, a few vet squads in transports for your troops. You'll want some protection for your tanks, I would take a hell hound or two, and a squad of bullgryns with a priest to give cover bonuses and to protect the tanks from assault, where they will die.
You can build around this as you want, the key here is that the atlas and tech priests provide the ultra reliable durability to an already durable tank. This works great on the already awesome executioner and removes a lot of the risk. As long as you don't out right kill your self with gets hot (highly unlikely) in one round, you can immediately repair the damage as the techpriests repair in the shooting phase so you can dole out your repairs after the tanks have already shot. Or you can use PoTMS if you don't have any damage to allow your tanks to focus their lascannons on one target and their plasma death cannon on others. Plus the atlas can tow a tank if you don't want to use a repair on an immobilized result.
Thinking about it, I would prob want a wyvern or two in the list for dealing with cheap hordes that you don't really need the plasma cannons for. Big important thing to understand is that the rest of your army is there to support this core element. It is extremely weak to fast assault units, as russes do not last long in a punching contest, and they are slow themselves so it makes it hard to get away. Protection units are needed, you can do this on the cheap with blob squads or conscripts, but since you have to have infantry squads anyways just to get conscripts, you'll get mileage out of two blobs as your troop choices that can tarpit and protect the russes. Bullgryns work pretty darn well at this too, they are not cheap so will require some thought, but they are very tough and much harder to remove than guardsmen, plus the cover bonuses they can provide for your tanks is a force multiplier.
Personally I like vets in the minimum troop choice role as you get more bang for buck without excess pts spent. Look at it this way, for 2 min platoons you are looking at 260pts with no options, for the same pts you have two vet squads in chimeras with a cheap special weapon. They are just more useful and fill your min troop requirements without spending on excess. Spend a little more pts and you still haven't broken the bank but will have two good troops to fill your spots and are more than just basic chaff.
You do want to think about objectives, which is why i also recommend the vets in transport, as they can move around to get objectives. Also some small scion squads deep striking can be used to grab objectives as well.
this basic list has 15 S7 AP2 blasts and 5 lascannons. Plus it has the hydra for ok AA, as air power isn't as decisive as it used to be, this should be enough to cover your butt and force your opponent to react to you. And you have a bunch of leman russ hulls with lots of repair abilities to keep them kicking.
You don't have to use executioners, but I feel they get the most use out of the repairs as they will be rolling gets hot. Where other tanks aren't going to be needed as much.
This is a frame work so feel free to build off of it and make it work for you. As long as you keep the leman russes as the primary and everything else supports them in some way, you'll do fine. You'll need an answer to fast assault units, and maybe a dedicated AV14 killer, but other wise you can handle MCs, tough units, and even large amounts of basic infantry.
As soon as I get enough plasma turrets I will be playing around with this, as well as needing an atlas.
let me know on how you would play this.
GG