i got one building design it's a inn/potion/enchanting building so that's cover. The public mines can be a mineshaft going trew a rock or hill looking thing that we can make easily. The portal i was thinking either a dome on pillars or a trophy with a globe on top with a year on how long the server has been up? The farming area don't have to be fancy but it could be a barn with a field area outside it or something.
That would cover the community buildings i think we need also including the spawn building that CJ or a mod will build.
It would also be cool if spawn chunks where in 0,0 or around that so we can tell people to go back there if they get lost?
edit. I forgot to mention my villagers are pretty much protected with a glass block in front of there cells and need redstone or breaking blocks to get to them. so the only rule is not do that i don't think we need new plugins the current ones work great and there always works around for stuff that plugins don't cover like blocks blocking my villagers!