Havoc, I had that thought myself. I'd quite like to, though there are a few issues. Chiefly time, and also that I'm not sure how good I can make it. If you'd be willing to edit in some mob-spawners...
There were a few things I was wondering about; could you put a plugin to prevent explosions breaking blocks (if areas are dark, I wouldn't want creepers ruining things). Also, would it be possible to make it lock night time until the evil is defeated (dread powers and that)?
Manco, I kind of like that idea.
We never did have a Spleef tournament.
EDIT: Actually, to make the ending more of a community thing, would people be willing to have different roles to fill in the adventure? So All who wish come along, but some of you I'd give instructions to in advance so at certain times you could say, 'Ah, well I know what happens here...' And tell people what to do next, or fill in an NPC role, or whatever.
Means of giving me more space to work with, and to make more of a tour of things. Obviously it'd take some organisation...
EDIT2:I can't get on to the server; probably shouldn't have updated my Minecraft.