I can see elements of the Audi A8 - particularly the rear end - but also there is a strong BMW influence in this design. I find this interesting, when Lexus first launched their LS400 in the late 1980's, it was clearly a Mercedes-Benz imitator.
But the car in the spy shots is far more Benz-like, which means it will probably be closer to the actual design.
BTW, I heard that Toyota are considering a Phantom/Maybach competitor - does anyone have more information on that?