Has any thought ever been given to doing a Hyborian age map? There are many excellent renditions of this map out there on the web, any of which can serve as the basis and starting point of a CC map.
I would envision play on this map to be much like Feudal war, with each major kingdom having a castle with auto bonuses each turn. You could even have a unite the land goal whereby one barbarian can conquer all the kingdoms.
I have more ideas for this map but I'll wait to see how much interest there would be in making one first.