I just put together a small shell-script, called "kinfinity" which emulates the changing wallpaper from fedora 8 on KDE. The idea is to change the wallpaper according to the time of the day and then set slightly different wallpapers for sunrise, day, sunset and night. The kinfinity code is inspired by a small script from Jihed Amine Maaref

The package to download includes the fedora Infinity wallpapers and requires you to create a cronjob, a symlink and set some paths. Have fun! :)

update 0.1.2: fixed a major bug which stopped the script from working from cron. damned. 

update: now also available via kde-look.org