Sent out emails/PMs to the four cover artists today, with their assignments and a template image for the proportions of the cover and where the spine goes. Here's the breakdown.
Book 1: - Jyre - Her climbing up Nightfall's tower (Dominus)
Book 2: - Ghost - Zombies and Hammerites on either side (redface)
Book 3: - James - Seated in a study overflowing with books (Ireth)
Book 4: - Lytha - Something to do with the Hammerite Castle (Julia)
Book 5: - Sheam - In the clutches of Balastar Ramirez (Ireth)
Book 6: - Nightfall - Dunno yet (Dominus)
I gave Ireth and redface more information than that... probably enough to get started. For Julia I tried to get the ball rolling with some speculation, as I am not sure yet exactly how the scene should be set up. Dom is already at work.