I think the wall should be built a bit further down the cliff. It doesn't have to be built right on the cliff itself.
Maybe we can make a sort of "promenade" along the cliff behind the wall. We just need to do a lot of digging to shape the thing properly. It could almost be like a lower ring or lower ward, but not too big either, and with a law on how tall it can be built (so that the lower ward doesn't build as high as the mountain and beyond and hides the majesty of the upper town).
Just throwing ideas, but I think the idea of putting the wall down there and carving down the cliff might work.
Also, what does PvP entail? Can we destroy other towns or just hurt people? It would suck if we could just destroy other towns' buildings.
EDIT: Yay the map! It's pretty epic... It's just a little annoying that underground signs sort of show up on top, but I'm not sure how that map could deal with that otherwise really.
EDIT 2: The signs seem to behave oddly, my signs don't even show up. Bah, minor qualms I guess.
EDIT 3: I also noticed that South is in the upper right corner. When you generated the map I was confused until I realized it was upside down :O I guess that's how it works?