what we know:
they made 7 million by 3/31/07 (sold
5.84 million of those; rest were in pipeline)
they were producing just over 1mil/month at that time
they were up to
1.5mil/month by june
they are currently at
1.8mil/month
let's assume:
they will sell out of 99% of what hits stores by 12/31/07
wiis made after 12/16 likely won't hit stores before 12/31/07
7 mil (06-03/07) + 2 mil (april/may) + 7.5 mil (june-oct) + 1.8 mil (november) + 1 mil (december) = 19.3 mil
that's right in the middle of the 18-20 mil range
they may have ramped up to 1.8 before november, as it was supposed to happen starting in august...but the only confirmation i can find is that they definitely are at 1.8mil in november
the fact that they may have been slightly ahead of the schedule above + the fact that they may be able to get some of the 12/16-12/23 wiis into the stores in asia before 12/31 + the fact that it'd be really good for them to be able to say they hit 20 mil by the end of the year (great for publicity, developer support, etc AND helps silence the critics saying they are purposefully undermanufacturing) = decent shot at them making 20mil, the top end of my range
market demand won't determine the final number, like it will with 360/ps3...supply will, so it's up to nintendo