This seems obvious, considering the large number of WWII-based maps. The idea is to build scenarios based on the actual historic situation (i.e. starting territories and army numbers) at a given point in history on a particular map. For example, "WWII 1939 scenario" on one of the WWII Europe maps would reflect the actual military/political situation in 1939, with territories and armies allocated to the major Allied and Axis powers (Britain, France, Nazi Germany, USSR, Italy). "WWII 1943" would also be interesting, since you would have US/Britain in place of France. Smaller nations would start as neutrals, or allied to the appropriate major power.
Other historical scenarios could be built for other real-world maps... such as the US Civil War map.
I hereby request access to the Beta site for designing scenarios.