Yes i know that one! Red ugly screen, not only in
KDE, but in Gnome, Xfce and Windowmaker also
And i have found them all
for globals change
etc/X11/Xsession where it says xsetroot -solid "#B20003"
change that for blue in "666699" (or whatever color but red)
well i said globals but mandrake screwed more files
all in the line with xsetroot
for kde /usr/bin/startkde (u can disable the splashscreen also)
for gnome /usr/bin/startgnome (can't disable splash from here
but there is a workaround)
for Xfce etc/X11/xfce/xinitrc
for WindowMaker /usr/X11R6/bin/startwindowmaker
if you want a wallpaper instead of solids i think you can use
xli (man xli haven't tried it yet)
good luck