I'm of a similar belief. Where do you think the Jomon - Ainu fit. The oldest (undisputed) Mongoloid skeleton ever found is 10,000 years old.
The Jomon I'm no expert on, but I've a colleague who has completed linguistic studies of the Ainu dialect (which is quite different from native Japanese-which is derived from Korean, despite what the Japanese might want to believe), and his conclusions were that Ainu is a derivative of Turkic. What branch, I don't know. The details he explained to me kind of went over my head at that point, but this is another suggestion of the common origins of Caucasians and East Asians, at least to me.