Someone seems to forget you could see XP SP3 on cd up until 6/30/08 while some prebuilds are allowed to sell with XP until 1/1/2009. That question is answered at Microsoft.
"Can I still buy Windows XP now? I'm confused. Some places have it, some don't.
We understand your confusion. On June 30, Microsoft stopped distributing Windows XP as a stand-alone product shrink-wrapped in the store. We'll also stop sending it to Dell, HP, Lenovo and all the other major PC manufacturers who would sell PCs that exclusively run Windows XP.
All and all, Windows XP isn't going to disappear overnight. If you need Windows XP, you can still get it through what we call "downgrade rights" that downgrade a new PC with Windows Vista Business or Windows Vista Ultimate to Windows XP.
Also, you may see devices called Netbooks or ultra-low cost PCs (ULCPC) running Windows XP Home. We intend to sell Windows XP Home for these machines with limited hardware capabilities to run until June 2010. (Read about the ULCPC program on Microsoft Presspass.)
You may even still see copies of the software, or computers pre-loaded with it, as stores and PC makers work through their inventory. Smaller, local PC makers—known in the industry as "system builders"—can continue to sell PCs with Windows XP until January 2009."
http://www.microsoft.com/windows/windows-xp/future.aspx
Note that doesn't seem to apply to certain exports or something else? A youtube on it can be seen at
http://www.youtube.com/watch?v=7inTcxLm2Ss
The problem there is trying replace the factory preinstall with a ??? version of XP and it simply not working. Using a partitioning tool to shrink the origianl primary down for a dual boot would likely fail as well if this some kind of ? "unsupported" XP for obvious reasons.