Between jumper cables and vehicles, you could have a “static” base consisting of a power generating vehicle and/or solar array, a stone wall, a series of pits, a series of 1x1 tile turrets (2x1 if using funnel+watercannons), a few floodlights, and a vehicle with a crafting array.
To make such a base “feel” static as opposed to just being an extension to existing mobile bases, I’d recommend adding a new series of vehicle parts. They would be extremely powerful, but so heavy that any vehicle they are attached to would be forced to be stationary. I’m talking 9,000,000 tons heavy, far beyond the lifting capacity of any vehicle (excluding impractical monstrosities like the Big Bertha).
Nuclear Reactor: More efficient than the micro/advanced reactor CBMs due to economies of scale, would produce upwards of 10k power per uranium, and would automatically turn off when batteries are full.
Fusion Reactor: Produces as much power as a 10x10 grid of quantum solar panels in a single day for no significant cost. Downside: Attracts hordes and nearby overmap tiles may get invaded by portals.
RTG: Produces a very small amount of power, constantly, forever, at no cost. Light enough that you could mount an RTG or two on a vehicle if it was big enough, but still too heavy to be practical on mobile vehicles.
Advanced Forge: Can only be charged by a nuclear or better reactor. Cannot be charged by traditional vehicle batteries. Required to craft and enhance advanced weapons.
Stone Pelter: Large turret that uses stones as ammo. Due to it’s shoddy construction, it must be weighed down with dirt to mitigate recoil - this makes it too heavy to be practical on a mobile vehicle.
I’d say a mod of this nature would be quite feasible. Blazemod probably contains all the json’s and code you’d need as a template to make a base construction mod. Even the advanced forge wouldn’t be much harder than making a new vehicle tool, giving it a new ammo type, and only allowing certain reactors to produce that ammo.
Summoning hordes might be trickier, but generating noise is easy and adding hordes shouldn’t be too difficult.