This gives me a bit of a chill. If I were an executive at M$, I'd be worried.
This community (assuming their project is successful) will have neatly parried the only compelling reason for the typical early adopters (gamers) to install Vista. Combined with the numerous bench marks out there on gamer sites that indicate that games run significantly slower on Vista as compared to XP on identical hardware, this may end up being HUGE.
Hacked DX10 for Windows appears
The Alky Project
Falling Leaf Systems
DX 10 Wiki
Taken from: http://groups.google.com/group/alkyproject-announce/
We at falling leaf systems are proud to release a preview of our
DirectX 10 compatibility libraries. These libraries allow the use of
DirectX 10 games on platforms other than Microsoft Vista, and increase
hardware compatibility even on Vista, by compiling Geometry Shaders
down to native machine code for execution where hardware isn't capable
of running it. No longer will you have to upgrade your OS and video
card(s) to play the latest games.
The current preview allows you to run a number of examples from the
DirectX SDK on Windows XP. They're not the greatest thing since sliced
bread, but we want to whet your appetite.