There seems to be a small community of DIY vehicle builders, but they tend to stick to forums and such. I think because of liability issues (and rules for cars are pretty strict as they are), there isn't a lot of sharing between builders beyond the basic frame

I don't know how reliable things like CANpie or Can4linux are (Controller Area Network or CAN used for internal systems communication in vehicles, and these are open source)

Speaking of vehicles, one design I'd like to see, even just for farms or for private property use only, is the "Rocker Bogie" design. It's the same system used by pretty much all NASA rovers since Sojourner

https://en.wikipedia.org/wiki/Rocker-bogie

Even though I've seen NASA use it since I was a kid, what really took my imagination in the direction of the Rocker Bogie, is Simon Stålenhag's excellent artwork

First, it was this one called "Missing Person"

He's since used the same vehicle design several times in other artwork. Each one is eerily beautiful in a hauntingly post-apocalyptic way

Looks like the interior of this style of vehicle is a cross between camper, research lab, and transport

Although the front is hard to see, it's well lit inside and seems spacious

Yeah, if I'm ever building a vehicle to carry me through an apocalyptic environment, it would definitely be a Simon Stålenhag inspired rocker bogie type

There are a lot of research papers on the Rocker Bogie layout, but almost all of them follow some version of this