Seems to me that the desktop posted is of a high enough resolution that you could edit it in GIMP to make wallpaper.
I liked it, couldn't find it either, so i did just that harryc...http://conradshome.com/images/default.png/
it's from a 1680x1050 shot like the above one.
for future reference... the backgrounds are in:
desktop-backgrounds-x.x.x-x.noarch.rpm (seem to be only tiles in the propaganda directory)
desktop-backgrounds-basic-x.x-x.noarch.rpm (just one default and several "space" themed images)
desktop-backgrounds-extra-x.x-x.noarch.rpm (this is where the most variety seems to be)
with x's being version numbers... I went through like 50 different versions of those rpm's and still didn't find this specific wallpaper
P.S. 7zip extracts RPM files (which contain .cpio archives, that 7zip can also extract) for anyone else who might need to do the same
Couldn't find those neither. tsk.