Here are three other Microsoft vaporware that went further than SDK's and never really materialized.
Next-Generation Secure Computing Base
WinFS
Xbox360 backwards compatibility
Microsoft has a tendency to tout non-existent products to erode or slow the market and customer base of a competing product. My first two examples are technology that was to be included in Windows Vista. I'll admit the last one did work in some cases but not so well in others and that's not good enough for WWE Wrestlemania 21 fans or DDR Ultramix 4 aficionadoes.
Microsoft openly mocked Nintendo's plans for the Wii and motion control but now Nintendo is back on the threat radar so Microsoft is going to tout non-existent products to try to keep people on the fence and in their camp. Can't believe Microsoft until it's up and running on your system as advertised. You might call it the Microsoft "ME TOO!" phenomenon.
Meanwhile Nintendo has been shipping product for two years and is wildly popular now. Nintendo is probably even making money on the console sale itself since it's mostly a Gamecube with wireless LAN/PAN and SD cards ie cheap but reliable established technology. But Nintendo has had more experience with lean times, something Microsoft has never really known.
