Any way to get these?

You can use the concrete foundation as a really thick wall. Otherwise the answer is mods, check the nexus if you have the PC version.

Really hoping the answer is not just mods for those of us on console. I would kill (literally.. It is fallout after all), for building options with less of a shanty town thing going on. I know its the wasteland and all but if the BoS, Enclave, Institute and the rest can manage to build huge concrete/metal fortresses so why can'y we? I know walls don't do anything really anyway in terms of defense but still..

The concrete foundation is all I've found. I built a tower out of them with a couple artillery guns on top. But they are thick (like the size of a large floor tile) and without something to latch onto, like a staircase, can be difficult to line up properly when stacking. They are the only wall you can really stack, though. Wish you could stack normal walls.

The foundation is nice for repairing the castle walls.

Else the solution is mods, overall its an need for more solid / better looking parts. How about an guard post who is an turret position, lift the turret up an bit and protect it.