Mhhh, well as someone who lives in japan I can tell you it is not getting any normal, check this Website
www.kakaku.com
It posts every electronic product in japan, just make a quick search for wii, and you will see that it doesn't appear in anyplace near the top.
By the way, this page it's updated everymoment and has database of shipments to virtually every retailer in Japan.
See you











I think 40 million should be the maximum for the DS though...