like cybrex said. once the game gets closer to alpha there will be a crowdfunding campaign (more than likely anyways) where the devs will give access to alpha testing or possibly beta or other such goodies for donation milestones by an individual. so just some patience is all. soon the time for the kool-aid will be upon us
Underground is confirmed some where, all you need to do is dig enough to fit the buildings such underground, there was a few posts on it a while ago about what people would do or what they would build. As my time is limited on the forums I cannot link them
And yes to a incredible size construct if constructs are as infinite as predicted then you can build whatever size deathstar/starkiller base you like, you'll just have to get both the man-power to build it and the resources required.
However, I must note that it has also been confirmed that there will be no super-weapons that are capable of destroying planets. Again can't link because of time .. But think of it this way, if there was a weapon like that then how would you balance it when there are countless territories on each planet, and even more territories that could be orbiting said planet?. It would be a cluster-**** to work with an create a acceptable outcome if a guild had that kind of power, not including what would happen if you tried the super-weapon on a arkified site.
