Cool, thanks a lot Madmanntis, and welcome to the Glest forum.
Regarding Earth and Sky, they're on hold right now since I'm really taking an interest in Sun and Moon and they'll require plenty enough work on their own. Looking at the horizon, Earth and Sky touch but stay totally separate, as related but opposing things, similar to how Sun and Moon follow roughly the same path but are totally different or how Technology and Magic are both ways of understanding and controlling the universe but are still very much in conflict with each other. I see Glest as being all about that sort of relationship, so that's where I got the idea for Sun and Moon and then Earth and Sky. They also loosely correspond to the four elements, but that wasn't really intentional.
It does look like I'll have a lot of good help already, but since about twenty units and a few buildings still need to be modeled, textured, and animated, there should be plenty of work to go around, and that's just to get a regular Magitech-sized tech tree, which is a lot smaller than what I have planned for "some day".
I'm on spring break right now and I'm planning on putting up some concept art and more detailed descriptions of the units when I get back, as well as a to-do list of what all needs to be done. That's going to be a long list, I think. I might also go ahead and record some of the unit speech while I'm away, since that should be pretty easy and it might give a little insight into the units' personalities.