Utterly Mad

At least two of these corporations already exist with SiegeWorks and Lork-Tech, although SiegeWorks isn't Terra Solus based anymore, they have an entire different planetary system of their own.
But before space travel was widely used it's likely both of these companies would own large amounts of land, they were supposed to be fairly influential.

Do you want me to include them in? I can. Hell I can put up The Euro Wars thread and we can tailor a bloody/economics based warzone together.