As for first principles, remember how I said the best, or ideal government would be the one that most resembles an image of the trinity? Well, instead of going through all those abstractions, we could cheat and simply use a system of government that the Holy Ghost himself instituted, and that would be the Catholic Church.
The Catholic Church is basically a monarchy, except that it elects its own rulers. It has a system of government that is actually quite personalized, as it is broken up into diocese. Each bishop has close to full authority over his own diocese, with the priests under him. A bishop is not going to interfere in another diocese (at least not directly), so each one is sort of personal to that region (kind of like a republic, in that it is more approachable to normal people). Then we have the Pope, who spends most of his time functioning as a bishop would (at least, back before Vatican II), the main difference between him and a bishop being that he was the final say on disputes concerning faith and morals.
So, I say we have a system of government that resembles how the Catholic Church runs. We would have semi-rulers, who had jurisdiction over their own lands, with a ruler at the top that was elected by these semi-rulers.