Official press release: http://www.scei.co.jp/corporate/release/071009ae.html
It has no PS2 BC either (I didn't think they'do this in Japan).
However, the current 20 GB and 60 GB models will continue to be available and got a ~10% price drop.
The price difference between the new 40 GB model and the 60 GB is smaller than in Europe (25% vs 33%), probably due to the fact that in Japan, the PS3 got a price cut even before it was launched if I remember correctly.
My Mario Kart Wii friend code: 2707-1866-0957