Asheshouse is right about SRTM data. A map could be built quickly from them. The difficult, or better say, time-consuming part is what follows. In particular, detailed maps with historical airfields and dedicated buildings and textures (e.g. Slovakia) may take a many-people team years of research and work.
On the other hand, I guess that adding another generic-looking map with textures and buildings from the current stock game will rise lots of eyebrows to say the least.
My (personal) two cents.
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