Here are some of the videos used. Maybe you can recreate them for DeskScapes. http://nashkrammer.blogspot.com/2011/03/my-dreamscene-videos.html
Try looking around here: http://www.google.com/search?q=Half+Life+Dreamscenes+for+Vista&sourceid=ie7&rls=com.microsoft:en-us:IE-SearchBox&ie=&oe=
The program was called Dreamscenes in Vista, btw.
I am very confident that the ones I am looking for where done by Valve, they where not screen caps of any kind it was definitely original work developed specifically as a dream.
My Googlefoo is strong but has failed me here, it seams as if they have been cleansed from the internet.
Thank you for your effort regardless.