Hm. Is it thread necromancy if it's your own thread? And I think we've pretty much covered it: maaaybe in a no US in WWII scenario the Soviets might overrun all of Europe, but they're unlikely to absorb territories with a population larger than the entire pre-war USSR: even all of OTLs Warsaw pact might be a bit much to swallow, although Poland (as a land bridge to Germany and for old times sake) certainly is a possibility. They're not going to absorb China (although a Soviet Manchuria, Korea, Xinjiang and Mongolia as SSRs are hardly impossible: heck, if Xinjiang is Soviet, a Soviet Tibet is not beyond all probability). Soviet Iran is a bit iffy, although as a Soviet puppet it is plausible.
Of course, much depends on who develops the atom bomb and when: the Soviets certainly will be in a better position to hold onto bigass territories if they get it first or too quickly after the first for enemies to build up an arsenal!
Bruce