I don't know if I can sign you up, GamExtremist, as your doctor says no.
Oh well... Ulm you say.
I think I see a pattern here, as the two nations not taken yet, C'tis and T'ien Ch'i, are both close to Ermor.
So to those that hesitate:
* Rivers block movement when there is no bridge available.
* C'tis has powerful priests and every T'ien Ch'i mage is a priest.