It would be neat to be able to save blueprints of vehicles (through the construction menu for example), mostly to be able to share a more complete view on your vehicles on the forum but also to be able to reuse designs and maybe even be able to add constructed vehicles to the spawning in world generation and replicating bugs.
This actually makes me think that blueprints of buildings would be cool, too. You activate it, and it places a ‘trace’ of the building on the ground. Activating it prompts the construction of the given thing. It’d be a cool way to speed up making something like a small wilderness fort, or be a neat little piece of treasure you can find in odd locations.