With the recent long thread on Medievals and Byzantines I think that the posters made a really poor case. Both the Medieval and Byzantine eras were about a thousand years long. If Hat were to consider making anything it would need to be made more precise.
With the Hat range for El Cid they hit a six (English readers) knocked the ball out of the park (American readers). There were 4 sets for the Christian forces and seven for the Muslims, covering two distinct groups.
So although personally I have little interest in either Medievals or Byzantines at present maybe those who do should post again explaining what they would like to see and if Hat needs to produce both sides or if it is an army for which an enemy already exists.