well what about "Stalins Missed Chance"? Y'know the alleged planned invasion of Nazi Germany that the Red Army was tinkering with? If the Red army had pre-empted Barbarossa and caught the Germans with their pants down so to speak, maybe make the Red army a little better prepared(perhaps a POD with a smaller purge or the Russians learning more from the winter war) you might stand a chance of seeing the Russians pulling up just across the channel from the English in '45 or even earlier. The allies may have tried to mount a western invasion on the channel coast of France, but until 42 the US army didn't even have the Sherman tank which in spite of being widely considered a death trap was light years ahead of the Lee. Besides without the mustang(and thus escorted bombing raids into Germany), an effective air campaign would have been considerably weakened, and the US army would not have learned the lessons of Operation Torch which would have cut the effectiveness of any Allied invasion force in half.
In short I could see this happening. but the Russians have to be a good bit smarter and tad bit luckier than OTL. Not completely unbelievable, but not exactly a small difference either.