I had a cool idea for a third vehicle that focuses on long range fire support. It's artillery vehicle that would be used instead of the tank or APC, a howitzer. It has low armor, mostly enough to protect against ballistic small arms, but wont stand up to even a lightly armored tank or AP jeep toe to toe. It has to deploy from its mobile mode to fire the howitzer, and has a unique secondary mode I think you guys are gonna find cool, so let's get into this.
The safari is a decently heavy lightly armored artillery piece, its design is fairly short but wider, it's an eight wheeler with 4x4 and good suspension while driving, and when it deploys, the wheels are anchored, and the safari raises up like a utility lift with the cross connecting struts. When deployed, a telescopic cannon measuring 5 meters detracts, and after about 7 seconds, is ready to begin firing. The cannon fires somewhat like a mix between a sniper rifle and a rook chess piece. It can only fire in the direction it faces, but the projectile is FAST, and decently devastating, the catch is that the shell only primes after it has crossed 15-20 tiles, and if it collides with a wall or unpassable object, it will tumble harmlessly onto the floor. If it hits someone before it arms, they are knocked down with heavy damage, and the shell is mostly unperturbed, as it continues on its merry way. After the shell arms, the drivers will hear a beep, and the first thing the shell collides with will trigger the explosion. Due to its raised position, the shell will pass over small obstacles and machines like a high throw grenade, but humans and xenos standing up will still trigger it. There are a few shell types I've devised, standard HE and AP shells, OT shells, maybe a bunker buster shell that does limited personnel damage but heavy anti building/armor damage, at the cost of speed. I do have one last shell idea though: a proxy shell, which is primed manually and detonates manually or when within 1 tile of a non almayer ID wearing entity, perhaps at a cost of accuracy or damage. Once the safari has been deployed and is able to fire, the driver becomes the loader, choosing via computer which shells to load from storage, and being able to turn off safeties to load faster with the added possibility of malfunction when loading.
The secondary mode, instead of the usual secondaries, consists of nothing by default, but it can be loaded by powerloader with: mounted HMG, regular/flame sentry, flag, mortar. You can only use these secondaries when the safari is UNDEPLOYED, and are handled by the gunner.
The sentries act as they normally would, with a 360 degree firing arc, but they have to physically turn around to engage targets. The flag would give a CO level buff to all three order types, but if the tank is damaged while the flag is flying, there is a chance for the flag to be damaged and the boost to be lost. The mounted HMG would work basically the same as regularly, but with the gunner able to rotate it with alt click instead of a wrench (it's loaded onto a swivel ring.) The mortar would work the same as normal, but it can only be loaded by the gunner if they grab a mortar shell with their hands before getting in, or by loading a mortar shell into the howitzer shell storage, then having the gunner grab the shell through storage.
Ammunition for the howitzer and mortar are loaded by clicking on the rear side of the howitzer with the requisite shells, which are put into storage. If the rear of the howitzer is damaged enough there is a chance for the ammo supply to be damaged, which will give a warning to the crew and give them a limited time to escape before the inside of the howitzer explodes ( this may also happen if the loading safeties are turned off and a malfunction happens.) The crew members embark on the sides like the APC, and the doors can be locked.
Upgrades for the chassis are: light chassis, doesn't impair movement, at low protection, heavy chassis for the reverse, and tactical/utility chassis, which has basically no protection at EVEN FASTER speeds than normal, but with a faster loading/retrieving speed and the ability to prepare a round and detract the cannon before you deploy it for tacticool quick setups. Utility upgrades include a thermal/IFF Camera for highlighting hostiles at range and telling friend from foe at a glance (more useful for HvH), Shell camera (which lets the gunner "watch" the shell as it fires and lands), and fulton winch which can either be attached to the dropship from inside to deploy it wherever the dropship is over the colony, or activated on the ground for the POs to grab to retrieve the tank. Retrieving or deploying the tank is slow and cumbersome, which means you can't fulton anyone else (or deploy paratroopers if that gets added) until your next flyby. There could also be an increased storage bay upgrade, but I'm not sure how many shells is too much so I'd leave that for devs to decide. The last upgrade I thought of is a supply beacon that can be turned on while the safari is deployed, and ROs can send crates to it through the Echo pad, landing around the safari with some inaccuracy.
I really enjoyed brainstorming this big chonking gun, let me know what you think, tell me if I missed anything, or if you have any ideas of your own to add to it.