I think the actual quote was "around the world" not in homes
http://themindchannel.blogspot.com/2010/01/ms-over-39-million-xbox-360-consoles.html
I do think the 360 is undertracked a little though because in no way do I see that many consoles on the shelfs or in the warehouse this close to after christmas. That many consoles would equal to around 2 months worth of sale "give or take".
But again let me say that in no way am I dishing vgcharts because with such large numbers that are involved here spread around so many countries to be only off a couple hundred thousand is something really great.