Whoa
Hey again,
Between your mobile hackspace and @Matthias’s '68 reconverted firetruck-in-the-making, why would we need a homebase or spots for harmonious hackathons? 
If you want to create your own project here on Edgeryders, go ahead and do it. There’s a caveat though: there are over 130 projects already and many of them inactive for obvious reasons. If you want a space to coordinate your work, that would be the way to go. If you want to actively look for collaborators I suggest you go where they might be already: on the top of my mind I’d recommend Kiderwind (open-source project which aims to harness the wind at high altitude in order to generate power), @Billy_Smith's OSHW, or Harmonious Hackathons which is becoming quite popular. Once you post inside any group, you automatically connect with its members (get notifications of replies & new content if you want to). Your choice of course, welcome again!