/etc/kde should be a symlink to /usr/kde/3.1/share/config and /etc/X11/xdm should be a symlink to /usr/kde/3.1/share/config/kdm
why?
Configurationfiles should be located in /etc :)
why they should be in /etc?
maybe to find them oO (/etc/X11/xdm is a typo, of course it should be /etc/X11/kdm/ ;D)
kde configuration is used to be in {$KDEDIR}/share/config, so this could create confusion more than simplicity, or, this will neither be noticed. Also, while multiple version of kde can exist on the same system this can't be done.
Then name the symlink kde3.1 or something like that, it took me a lot of time to find the kdm config files, which I expected to find in /etc/X11/kdm.
you should not expect that, the standard path for kde configuration file is: {$KDEDIR}/share/config, but if for you a symlink in /etc can be useful, you are free to make it on your system