Couple of hours? No way! It takes longer than that just to make a map. Now I can imagine a "short cut" way of making a scenario like that - you could take R8XFT's Anno Domini mod, make (or import) a Europe map, change the civs to those of the Middle Ages, place some cities, and start everyone off in the last age, and voila. That would be a very good way to learn modding, I think, and it wouldn't take very long since you wouldn't have to add units etc. But still, as I say, if there's a scenario you'd like to see made you should have a go at it.