For the SS and Siberians in the various WW2 scenarios, and I guess any similar situations, would it be possible to give them some production by way of a "lend lease" system rather than owning a city?
IMO the Siberians don't deserve to exist as a separate entity in any scenario anyway (see tm.asp?m=1543909 ), but if they do....
Edited so clicking on the link actually works!