I highly doubt that Microsoft will let there be 360 shortages as they want to corner the market in this new race of console success but Joystiq has heard otherwise:
In a September 15th research report published by Deutsche Bank Group, Takashi Oya and Kazu Ejiri suggest that Microsoft’s decision to offer just one Xbox 360 SKU in Japan may be a result of lower-than-expected production output of Xbox 360 units.
They write, “We believe Microsoft wants to offer the scaled-down version but may be looking to control sales because of the possibility of not being able to meet initial demand.” They go on to note that they believe that Microsoft will eventually sell the scaled-down Xbox 360 package without the hard drive and extra accessories once the company is able to rustle up enough of the consoles.