According to Gamefront.de Nintendo´s DS shipments in Japan passed 20 million units during the last week. (Maybe it was mentioned in the financial statement, too but that´s when I started to wonder.)
According to vgchartz.com the Japanese LTD sales of Nintendos DS are 19.86 millon units.
If that´s true there are only 140k units left in stock which is a sell-through of 98.4% indicating there is still tight supply for the DS.
Is the DS still sold out in Japan? This doesn´t seem to be possible. Are 140k units of national stock enough to have the console available in every store? I don´t think so, too.
Unfortunately, gamefront doesn´t provide a source for it´s news but that´s what they generally do.