usb stick booting multiple linux isos

gistfile1.txt

# mkfs.vfat -n multi-linux /dev/sdc1
# mount /dev/sdc1 /media/usb
# mkdir /media/usb/{boot,iso}
# grub-install --force --no-floppy --boot-directory=/media/usb/boot /dev/sdc

... download a bunch of isos ...

# ls /media/usb/iso
debian-7.0.0-amd64-firmware-netinst.iso*            grml64-full_2013.02.iso*     memtest86+-4.20.bin*  tails-i386-0.17.2.iso*
debian-live-7.0.0-amd64-gnome-desktop+nonfree.iso*  kali-linux-1.0.3-amd64.iso*  memtest86+-4.20.iso*  ubuntu-13.04-desktop-amd64.iso*
# cat <<EOH>/media/usb/boot/grub/grub.cfg

# Config for GNU GRand Unified Bootloader (GRUB)
# /boot/grub/grub.cfg

# Timeout for menu
#set timeout=30

# Default boot entry
#set default=0

# Menu Colours
set menu_color_normal=white/black
set menu_color_highlight=white/green

# Boot ISOs

menuentry "TAILS - The Amnesic Incognito Live System" {
    set iso="/iso/tails-i386-0.17.2.iso"
    loopback loop $iso
    linux (loop)/live/vmlinuz boot=live config live-media=removable nopersistent noprompt quiet timezone=Europe/Stockholm block.events_dfl_poll_msecs=1000 splash nox11autologin module=Tails findiso=$iso quiet_
    initrd (loop)/live/initrd.img
}

menuentry "GRML - the sysadmins best friend" {
    set iso="/iso/grml64-full_2013.02.iso"
    loopback loop $iso
    set root=(loop)
    configfile /boot/grub/loopback.cfg
}

menuentry "Debian 7.0 Wheezy AMD64 Installer (netinst, firmware)" {
    set iso="/iso/debian-7.0.0-amd64-firmware-netinst.iso"
    loopback loop $iso
    linux (loop)/install.amd/vmlinuz
    initrd (loop)/install.amd/initrd.gz
}

menuentry "Debian 7.0 Wheezy AMD64 Live system (GNOME, firmware/non-free)" {
    set iso="/iso/debian-live-7.0.0-amd64-gnome-desktop+nonfree.iso"
    loopback loop $iso
    linux (loop)/live/vmlinuz boot=live
    initrd (loop)/live/initrd.img
}

menuentry "Kali 1.0.3 - Penetration Testing Linux Desktop amd64" {
    set iso="/iso/kali-linux-1.0.3-amd64.iso"
    bootoptions="findiso=$iso boot=live noconfig=sudo username=root hostname=kali quiet splash"
    search --set -f $iso
    loopback loop $iso
    linux (loop)/live/vmlinuz $bootoptions
    initrd (loop)/live/initrd.img
}

menuentry "Kali 1.0.3 - Penetration Testing Linux Desktop amd64 (forensic)" {
    set iso="/iso/kali-linux-1.0.3-amd64.iso"
    bootoptions="findiso=$iso boot=live noconfig=sudo username=root hostname=kali noswap noautomount"
    search --set -f $iso
    loopback loop $iso
    linux (loop)/live/vmlinuz $bootoptions
    initrd (loop)/live/initrd.img
}

menuentry "Ubuntu 13.04 AMD64 Desktop" {
    set iso="/iso/ubuntu-13.04-desktop-amd64.iso"
    loopback loop $iso
    linux (loop)/casper/vmlinuz.efi boot=casper iso-scan/filename=$iso noprompt noeject
    initrd (loop)/casper/initrd.lz
}

menuentry "Memtest86+" {
    linux16 /iso/memtest86+-4.20.bin
}
EOH