We are working on our first Servants of Gaius supplement, The Guidebook to Aegyptus. These will be PDFs (later bound into one large print volume) and each covers a single province. Let us know what you want our guidebooks to contain and which provinces you hope to see soon.
For those who haven't heard, Servants of Gaiusis our new Roman RPG (PDF HERE). it was just released in PDF and comes out in print soon.