I currently work around this problem for xdm & xfs by storing my
   local configuration in /etc/X11/*, and using the following rc.conf
   variables:
   	xdm=YES
   	  xdm_flags="-config /etc/X11/xdm/xdm-config"

i have done this for a long time.  most of the files in /etc/xdm
(for me) are also symlinks to elsewhere.
   
      1.	Move the files that are likely to be modified
   	by the end user to a new set "xetc.tgz", and
   	only install these files in with "make distribution"
   	instead of "make install".
   	Enhance postinstall and etcupdate to support upgrading
   	changed files as necessary.
   	I've attached a list of files that I've identified
   	that are candidates for this.
   	This is my preferred solution.


at least initially, this seems like the best option.


.mrg.