This is just a rough map of my ideal Greater Germany scenario plus all the territory from the original Prussian and Austrian Partitions of Poland included. It looks uncomfortably similar to Nazi Germany at its peak, but that can't be helped.
Area: 959,734 km2
Germans: 112,910,796 (74.7%)
Poles: 23,863,151 (15.8%)
Czechs: 7,423,016 (4.9%)
Ukrainians: 3,218,836 (2.1%)
Slovenes: 2,149,114 (1.4%)
Italians: 957,011 (0.6%)
Others: 645,789 (0.4%)
I got the original map template from Wikipedia.
For anyone interested in the territorial makeup of this superstate, it is composed of:
Imperial Germany, Luxembourg, and Liechtenstein.
Austria-Hungary without Hungary, Dalmatia, or Bukovina.
Modern Burgenland with Sopron (Odenburg) and the surrounding villages.
Congress Poland with Bialystok region (the entirety of the original Austrian and Prussian Partitions).
This sort of state would probably have been formed with a point of divergence somewhere around WW1.
PS. I had a belated stroke of creativity and calculated that with Lombardy-Venetia added (just for fun), Germany's area would break the million mark. There'd be way too many Italians stuffed into the German goose, though.
Area: 1,006,516 km2
Italians: 16,913,034 (10.1%)
Germans would make up just 67.6% of the population.
See what I mean? It's not happening. You could hardly call it "Germany" anymore. They are very valuable regions, though. Hmm...
Gimme a Belfort?! No... now I'm just getting carried away... and that didn't work out very well last time.