The game stopped throwing me MoHs for some reason, so I had to go ahead until the two youngest French sons grew up. 16 avatars and 20 provinces. Here's the situation and save:

http://www.totalwar.org/patrons/pbm/NBTest1.zip

There are two nobles who are just about to return from going on Crusade and they possess the only dismounted knights in the realm. Their return would make a good trigger for the civil war. The King, his two sons, and one other general are on the British Isles, and would be a good third faction. Prince Louis and two or three other generals are in the south of France and northern Spain, making up another good faction. The middle nobles stretch from Rennes to Bern and could make up a good third faction.

Of course there are plenty of other ways to split it. Papal relations are near perfect, and we're only at war with the Reich, who won't accept a ceasefire no matter how many times I smash them and release the prisoners. I guess I could add money and buy them off, but it didn't occur to me before I uploaded.