Some of that was discussed in the Watcher thread. And in the Monster Scenario thread.
Editing a map can be simpler than it seems at first. Take any map and add one white dot to the far upper-right corner. That will increase the province count by 1 creating a province with no connections without shifting any other provinces.
The watcher mod creates a nation which makes it very hard to abuse, very unlikely to die a death from lack of dominion or stray random events, and has a starting spell version of "Eyes of God" to see everything that is going on (one thing I couldnt get rid of is it takes a global spell slot). It also has little invisible units that can move across the whole map so that you can position them to watch combats and such if you want to.
Here is another thread I found along these lines.
http://forum.shrapnelgames.com/showt...nts#post485570
I also like the idea that has been put forth in the past (cough cough) of a GM or some dom3 veteran role-player-type playing as an opponent nation. Go ahead and boost the nation mightily and preset them with an entire portion of the map, multiple castles at strategic points, extra units, a god not usually available as a god. Make them strong and well set so that the game becomes a giant alliance to take them out (kindof a lord of the rings type scenario tho I wouldnt go as cheesy as to make it exactly LoR)
Gandalf Parker