I just read a study which It gave me a new perspective on the topic of the sustainability of small-scale, local production of vehicles - not that new, small-scale local manufacturing businesses are more sustainable in and of themselves, but rather that the establishment of feasible low-scale production business models could cause a shift in the broader industry and reduce the current need for overproduction of vehicles.
(on a related note, I imagine that in the next decade, self-driving 'transport as a service' vehicles taking over from private ownership is likely to force the industry to reduce production anyway, and likely to lengthen the lifespan of vehicles, as needs and motivations in public transport are different from private - for example, Berlin's public transport U-Bahn & tram fleet currently have an average age of 28 & 20 years respectively)
I also had no idea that paint was such a huge cost in the process, and that body manufacturing is the most significant aspect requiring large-scale centralized production - so there's a potential advantage of digital manufacturing there.
Their case study was the Morgan Motor Company, which I've always been a fan of from a classic design point of view, but interesting to see the parallels between what they do and open source business models.
There's also a whole lot of really interesting discussion of modular design and manufacturing, i.e. the tension between making customization decisions early or late in the manufacturing process.
Read the full paper here: http://www.sciencedirect.com/science/article/pii/S0959652615002103
Open Access! yeah