Create multi boot USB stick/hard disk with whole iso/s on vfat/fat32 partition
keeping existing data untouched.

run this command as root (su -, not sudo)
live-fat-stick isopath stickpartition
e.g.:
live-fat-stick /home/geeko/openSUSE-Edu-li-f-e-12.2-1-i686.iso /dev/sdXY

To add various distribution iso to the stick, run the following:
For openSUSE : live-fat-stick --suse /path/to/openSUSE-filename.iso /dev/sdXY
For Ubuntu : live-fat-stick --ubuntu /path/to/ubuntu-filename.iso /dev/sdXY
For Mint : live-fat-stick --mint /path/to/mint-filename.iso /dev/sdXY
For Fedora : live-fat-stick --fedora /path/to/fedora-filename.iso /dev/sdXY

isopath should be full absolute path of iso image and the device should be
actual partition on the stick like /dev/sdb1, /dev/sdc1,/dev/sdc2...

The stick partition has to be vfat/fat32 format.

run live-fat-stick -l(or --list) to list the possible usb storage devices available.

It is possible to boot multiple distributions and iso images from same device,
should work with all recent openSUSE or Ubuntu live iso images. Fedora iso is
not copied but is extracted as it does not support booting from iso.