Multiboot USB using grub4dos and ISO images
Grub4dos download
http://gna.org/projects/grub4dos/
Grub4dos repository with newest versions by https://github.com/chenall
http://grub4dos.chenall.net/
Grub4dos guide
http://www.rmprepusb.com/tutorials/grub4dos
Grub4dos Example Menus
http://www.rmprepusb.com/tutorials/grub4dos/grub4dos_examples