It would be an interresting timeline. Unfortunately it´s complete unrealistically. Hitler was an insane fanatic who attacked at the first possibilty - after a few years of preparation. AFAIK he was very upset that he could not start the war in 1938 when he occupied the Czech republic. France and England were to cowardly to start the war then.I've always wondered how the war would have went had it started 4 years later than it actually did.
The Maus is actually cool. And I like the name 'mouse' for such a heavy beast. A lot of German engineering projects were quite cool, but of course most were a waste of ressources. However, you can see what happens if you let engineers do everything they want.