You know, there are Japanese forums with threads dedicated to when DS Lite shipments come in and which store to stake out in Tokyo. It has been sold out since it was first released.There are noticeable shortages across the US and Japan since Christmas.
Try 'since last March' for Japan. Seriously, I've yet to see any white NDSLs in stock ANYWHERE in Tokyo since launch day (March 18, 2006) ... Of course, I haven't exactly been looking everywhere (because I got one on launch day) but I've kind of kept an eye out for a few friends. So far, nothing.