A wallpaper I quickly made last night to go with my Flat icon set:
There are 2 wallpapers, one with just "kde" on, the other with "kde 3.2" on.
Both are transparent, so you can choose your own background colour. The colour used in my screenshot (preview 3) is a gradient from #ABAB95 to #C0C0C0.
Sorry if it is a bit crap :)
(Only really created for my use).