No matter how optimistic you are about the PS3 sales in the coming weeks, I don't believe the supply will be enough to outsell the Wii for more than about 3 weeks, and those weeks probably will not be consecutive, if there even are 3 weeks.
We should see the phats having a decent chance of outselling the Wii in the next 2 weeks, and the 1st run of slims outselling the Wii as well... after that, I think supply dictates that its probably not a possibility, unless Nintendo has really cut down their manufacturing/shipping.
That said, I do believe that the same issues will cause the PS3 slim to remain relatively high in sales, and demand, throughout the holiday season, and Q1 2010, until the "super HD release tsunami" is over with sometime in late March/early April 2010.