The last 'official' multi-boot version had this (courtesy of mika):

mika@lunge /mnt/grmlmonster/boot/syslinux % cat defaults.cfg
label grml-auto
 menu label Automatically load Grml for your architecture
 menu default
   kernel ifcpu64.c32
   append grml64 -- grml

include grml_default.cfg
include grml64_default.cfg
mika@lunge /mnt/grmlmonster/boot/syslinux % cat grml_default.cfg
default grml
label grml
  #menu DEFAULT
  menu label grml   ^Standard (2010.04-rc3, i386)
  kernel /boot/release/grml/linux26 
  append initrd=/boot/release/grml/initrd.gz  boot=live  apm=power-off vga=791 
quiet nomce  live-media-path=/live/grml/  boot=live persistent-path=/grml  
bootid=2bc11e22-a1fd-4bb3-b1e0-279726805fbf 

  text help
                                        Grml is a Debian based Linux live
                                        system for system administrators
                                        and users of text tools.

                                                         http://grml.org/
  endtext

mika@lunge /mnt/grmlmonster/boot/syslinux % cat grml64_default.cfg
default grml
label grml64
  menu label grml64 ^Standard (2010.04-rc3, amd64)
  kernel /boot/release/grml64/linux26 
  append initrd=/boot/release/grml64/initrd.gz  boot=live  apm=power-off vga=791 
quiet nomce  live-media-path=/live/grml64/  boot=live persistent-path=/grml64  
bootid=2bc11e22-a1fd-4bb3-b1e0-279726805fbf 

  text help
                                        Grml is a Debian based Linux live
                                        system for system administrators
                                        and users of text tools.

                                                         http://grml.org/
  endtext