Try Life and Fate by Vassily Grossman. It's not really alternate countries etc, but it is fiction set on the Eastern Front during world war 2. It has a similar framework to War and Peace, so it can be intimidating, but I found it incredibly rich in detail.
The guy who wrote it was a famous war correspondent during world war 2, and knows how to tell a tale.
http://www.amazon.com/Life-Fate-Review-Books-Classics/dp/1590172019
Hmm. I think maybe Life and Fate should be on my reading list...