I thought the DS was in short supply because Nintendo couldn't make enough!
Actually, this is an interesting point: if Nintendo is truly having problems meeting demand, then the sales shouldn't really go up much during the holiday season. Of course, you could argue Nintendo is stockpiling units for that time because it knows demand is going to be even higher, but either way, that would suggest that Nintendo is artificially creating demand.
Oh yeah, and half a million? Nice.