This is with the XFree86-xfs-3.3.6-20 package. When configured to use syslog (as is the default with Red Hat 6.2), the X Font Server (xfs) sends syslog messages to the "local0" facility. This is annoying for us, because we use the localN facilities for local purposes. No vendor-supplied tool should log to any localN facility by default. The "daemon" facility would be more appropriate. Even better would be allowing the user to configure the facility at run-time...
I like the idea of changing this as you suggest, but it is only realistic to do so if the XFree86 team thinks it is a good idea as well. I have asked the XFree86 team, and am awaiting their reply. I will decide what to do then.
At some point I will investigate changing it to log at the daemon level.
I've made this enhancement in XFree86 4.2.0-5.1 in rawhide. I'll submit this change upstream to XFree86.org as well.