I agree with you whole-heartedly on the phony 360 shortages... I have talked to people who work in videogames stores and departments and they told me they always have 360 in stock.
End of 2009 Predictions (Set, January 1st 2009)
Wii- 72 million 3rd Year Peak, better slate of releases
360- 37 million Should trend down slightly after 3rd year peak
PS3- 29 million Sales should pick up next year, 3rd year peak and price cut