Victor,
At present, VSP only supports the set of components you see there. Although they are aimed at aircraft, if you are creative, you can use them to represent things that are very different. I have had students model terrestrial vehicles in the past -- but I don't have any of those models.
http://hangar.openvsp.org/vspfiles/48
The soon to be released version 3.0 of VSP will come with a user defined component capability. We are embedding a scripting language in VSP and you will be able to use that to define new components using your own parameters.
When the user defined component capability takes more concrete form, we will extend the Hangar to also provide an online exchange for those components.
Rob