I have constructed a map using Kyriakos's Byzantine map. It takes place around the 14th century. The 4th Crusade has left the Byzantine Empire in ruins. There are nine playable civilizations:
Latin Empire
Pros: Strong UUs, hold the city of Constantinople
Cons: Surrounded by enemies on all sides
Empire of Nicaea
Pros: Have a good shot at retaking Constantinople
Cons: Turks could be a threat
Empire of Trebizond
Pros: Small, developed nation, fairly strong army for its size
Cons: Could be easily conquered by the Turks
Ottomans
Pros: City full of units, ready for expansion
Cons: Only start with one city
Despotate of Epirus
Pros: Isolated from the main conflict
Cons: At war with the Thessalonicans
Kingdom of Thessalonica
Pros: Strong army, source of iron
Cons: War with both its neighbors
Duchy of Athens
Pros: Strong UU
Cons: Too weak to pose any threat
Principality of Achaea
Pros: Source of iron, isolated from threat
Cons: Too weak to pose any threat
Seljuk Turks
Pros: Fairly strong army
Cons: Faces economical and diplomatic problems
Latin Empire
Pros: Strong UUs, hold the city of Constantinople
Cons: Surrounded by enemies on all sides
Empire of Nicaea
Pros: Have a good shot at retaking Constantinople
Cons: Turks could be a threat
Empire of Trebizond
Pros: Small, developed nation, fairly strong army for its size
Cons: Could be easily conquered by the Turks
Ottomans
Pros: City full of units, ready for expansion
Cons: Only start with one city
Despotate of Epirus
Pros: Isolated from the main conflict
Cons: At war with the Thessalonicans
Kingdom of Thessalonica
Pros: Strong army, source of iron
Cons: War with both its neighbors
Duchy of Athens
Pros: Strong UU
Cons: Too weak to pose any threat
Principality of Achaea
Pros: Source of iron, isolated from threat
Cons: Too weak to pose any threat
Seljuk Turks
Pros: Fairly strong army
Cons: Faces economical and diplomatic problems