Modding multiple shipyards per planet?

[dmm]

What would happen to spaceyards on ships or bases that were not orbiting a planet? Would those build extremely slowly? If not, why not? If so, then won't that make it all but impossible to build a ring/sphere world? (Don't you have to build them in place, using non-orbiting spaceyards, since the components are too big to transport from a planetary shipyard?)