In article <200101272219.OAA20487@zen.quick.com.au> you write:
>I'm still investigating this, but if others have seen evidence of
>config files being corrupted when dhclient-script is run I'd like to
>hear.

Yes we've seen this.  We have a dhclient-exit-hooks that reads in part:

  if [ x$new_filename != x -a x$new_dhcp_server_identifier != x ]; then
#    echo tftping $new_filename from $new_dhcp_server_identifier:
    echo "get $new_filename /etc/workstation-config" | tftp $new_dhcp_server_identifier > /dev/null
  fi

Back when we didn't have the echo commented out (which was back in 1.4R or 1.4X
days) we would sometimes see it output into /etc/resolv.conf. This is on i386.

cheers
mark