I'm indebted to Mikey for letting me know that we have now published the kit here. It's in 3 parts at the moment. There are, an X86, an AMD-64 bit and a Windows PE file, I believe there is also an IA-64 version which has yet to appear.
While I'm tipping my hat to people, I also need to thank Jesper, who pointed out my post "Getting started with Windows PE" relies on using the Windows Vista version of diskpart. He writes: "Diskpart in XP does not recognize removable storage devices like USB flash drives", and predicts (correctly) that I don't have XP any more to confirm this.
Finally both Jesper and Mikey were at the event I did in London called "Everything you want to know about Vista imaging". My slides got uploaded, but someone forgot to add the link to the Technet "post events downloads" page. Thanks to Mike for prompting us to fix this.
Update. Thanks to Mark who pointed out the download for WAIK is no longer working. You can get it as an image file here.