And I don't mean Win 7 / Metro UI guidelines, I have them up the wazoo, but I've changed jobs and need to start looking at the new Windows 8 DESKTOP design. I know it takes a lot of cues from Metro on Win 7 mobile but it's not the same and I can't find UI guidelines anywhere.
The guidelines for Windows 8 desktop applications are the same as for Windows 7.
That means that you'll find them here:
Windows 8 has two separate UIs: Windows Store apps (formerly known as "Metro-style apps") and Desktop.
Windows Store apps is the new, future oriented touch UI. These apps will typically run in touch environment where consumption (not production) of content is the main purpose of the app.
The Desktop UI is there for backward compatibility(!). It will be used by applications that need the full power of Windows. This UI is similar to Windows 7. Only minor changes to the look and feel, eg. squared button corners instead of rounded.
For the Metro part, there's some documentation about the UI:
Checklists with some about UI concepts (archived Feb. 2012) https://web.archive.org/web/20120208075631/http://msdn.microsoft.com/en-us/library/windows/apps/hh465424.aspx
Punchcut posted on their blog a good series about Windows 8 / Metro (Archived Dec 2013) and how to design for it.
It has 5 parts:
- Windows 8 solving the PC problem (Archived Nov. 2012)
- Windows 8: The New Modernism (Archived Oct. 2012)
- Windows 8: The Origin Story (Archived Oct. 2012)
- Windows 8: Microsoft’s Manifesto (Dead link, not on archive.org)
- Windows 8: Designing the Metro Experience (Dead link, not on archive.org)
Especially the last one is worth reading. They write about their experiences and gained knowledge (navigation concepts, branding, responsive design) while creating Metro Apps. There are even very practical tips like you should take CSS transform porperty for motion design, because this is GPU accelerated.
Your question is hard for me to understand.
If you mean "I want the UX guidelines for Windows Store applications (not Windows Phone)", they're available on the Microsoft website (Archived Nov. 2012). They're part of a more general overview of the UX of Windows Store apps. Those are the apps that run full-screen.
If you mean "I want the UX guidelines for designing apps for use in the Desktop mode of Windows 8", you should read the Windows UX Interaction Guidelines, paying special attention to the section on Ribbons (which are really emphasised in Windows 8's desktop mode). Those are the apps that run in windows, with the Windows taskbar and your desktop wallpaper visible.