Wesley wrote:

"There was a section of Russia's far east set aside as a "Jewish state" under Communist policy, IIRC. If so, 
I think that would've had Yiddish as its official language alongside Russian.

I've forgotten its name, unfortunately."

You're thinking of the Jewish Autonomous Oblast, or Birobidzhan. Yiddish is still one of the official languages.

Michael Chabon wrote a novel, The Yiddish Policemen's Union, set in a world where Israel was never established and the Jews displaced by WWII were resettled in Alaska.