It would mean some 87,000 units more than PS3 every week in average. Not entirely impossible if you consider the Kinect boost between Black Friday and Xmas, but the sales differences in North America will have to compensate the PS3 lead in both Europe and Japan.
You have also to bear in mind that 360 has no big title besides Forza (and I don't see Forza move HW) now that Gears 3 launched. PS3 on the other hand still has Uncharted 3 in the West and Ninokuni, the Idolmaster 2, FFXIII-2+bundle in Japan to boost its sales.