This is a Windows Whistler build I've been wondering about for over a year and a half.
All I know is that it was the first build with Luna, but it didn't have the XP Windows logo yet.

If you look on Whistler Build 2428 (I think) on Taskbar properties, it will have a screenshot of a beta Luna taskbar with the old Windows logo on it.

Now, I was wondering: Does anybody else know anything about this build? It's definitely unleaked.

2422 does not exist AFAIK, it's a mistype by Wikipedia

What's with the images in Whistler 2428, then? Were they just concept art, or from an actual build?

those screenshots of 2428 are real

You can't really count those images from taskbar properties as reliable proof of a build, even in XP RTM it's still some conceptish Luna rather than the final version...