I use grub-imageboot
to boot a floppy image
boot iso, harddisk and floppy images with grub2 and syslinux memdisk
This package installs a grub hook which integrates iso, harddisk and floppy
images into the grub menu.
memdisk can't boot every image see
http://syslinux.zytor.com/wiki/index.php/MEMDISK for its limitations.
'drop' your images in /boot/images/ ( configured in /etc/defaults/grub-imageboot )
and run update-grub2
this is on Debian, may differ with rpm or 'other' based distros
Of course, the trick is to get working images for use in /boot/images/
if you get stuck I can look further into it for you.