FOLLOW-UP: How-To: Make a Multiboot Live USB Stick

In the post "How-To: Make a Multiboot Live USB Stick", there are major enough errors to fix and changes to be made that I have made this a separate follow-up post.
The hardware is the same. However, the OSs in question have changed.
The smaller change is the removal of PartedMagic from the multiboot combination. I did not want to have to deal with extended partitions, and I figure that on-the-fly creations of live CDs for people in need (to keep) would be more effective anyway.
The larger change is the removal of PCLinuxOS 2009.2. As it seems, PCLinuxOS (as well as its parent distribution, Mandriva) refuses to work on a multiboot live USB (though it will work fine as the sole live OS on a USB stick). After installing more OSs, PCLinuxOS will give an error message that looks like, "This is not a bootable floppy. [emphasis is mine] Please try again."
Basically, your USB stick is apparently now a floppy disk according to PCLinuxOS. I knew then that sticking to that OS would not work.
I searched long and hard for a good KDE-based distribution that would turn on new users and work very well, and I came upon Sabayon Linux.

The following will be a sort of mini-review of Sabayon 5 KDE, the version I installed live to the USB stick.
Sabayon is based on Gentoo Linux, which requires users to compile the source packages frequently (at least once per use). This is not for the faint of heart, but many people enjoy it for the same reason that many car enthusiasts like manual transmissions (which are slowly fading away). This used to be a defining feature in many Linux distributions but has since been basically done away with, so Gentoo has kept it to please the users and to retain the super-bleeding-edge status of the OS.
Sabayon does not require this; it is thus more like a conventional Linux distribution, but it still retains the bleeding-edge codebase of Gentoo. This means that there are a lot of new cool and heavily tested features, making for a great OS experience.
Sabayon 5 KDE comes with a plethora of amazing applications. First, unlike many KDE distributions, Sabayon comes with Firefox and OpenOffice.Org (instead of Konqueror and KOffice) by default and integrates both applications very nicely. Second, it offers a great selection of games, and it even has real game demos like those for World of Goo, and it supports games like America's Army and Wolfenstein. Finally, it is built for media centers. It has a lot of powerful applications like XBMC to manage even the most complex media centers. The final statement (about media centers) is from my reading, not from my experience (as I don't operate a PC media center).
In addition to this, Sabayon 5 KDE implements KDE 4.3 in the best way that I've seen yet. It actually comes with the Desktop folder applet out of the box so as not to confuse new users. The Plasma panel actually works stably without crashing, as do the Plasma widgets too. Finally, the other KDE applications seem to work as intended without a hitch. The whole desktop experience really looks polished and stable, something that I can't say about other implementations of KDE 4.3.
The biggest downside to Sabayon 5 KDE is the relatively demanding set of system requirements. Even the newest (non-purposefully tiny, as in TinyCore or DSLinux) Linux distributions can support computers over 8 years old without sacrificing performance or the features that make them ahead of the (non-Linux) pack. Sabayon 5 KDE doesn't have as much of an advantage, as it requires at least 512 MB of RAM and 10 GB of hard drive space (along with a decent graphics card) to be installed and run well. Furthermore, the boot time is rather long even after installation.

This resumes the talk about the multiboot live USB. Again, this must be done in a Linux system. The partitioning scheme should be two 1 GB and one 2.6 GB ext3 partitions (for the OSs) and one 3.3 GB FAT32 partition (for storage). One can do this in GParted as described in the original post.
Successively install (and test, as described in the original post) Linux Mint 7 "Gloria" Xfce and Sabayon 5 KDE into, respectively, the 1.0 GB partition and the 2.6 GB partition through UNetBootin as described in the previous post.
After these have been tested and are determined to work, download to the desktop the Fedora 11 "Leonidas" GNOME ISO image. Burn the image to a CD but do not do anything to the original image (on the desktop) otherwise. That step is crucial!
Boot into the Fedora 11 live CD, and after logging in, go to "Add/Remove Programs" and search for, check, and apply "livecd-tools" or something like that. After that is all done, open a terminal window and navigate (through commands like "cd" and "ls -l") to the folder (on the original Linux desktop) where the ISO image is.
After this navigation, type into the (still-open) terminal the command

su -c "livecd-iso-to-disk /dev/live /dev/USBDEVICENAME"

where "USBDEVICENAME" is the name of the device and partition (e.g. "sdf2"). To confirm the partition number, type into the terminal (before typing the previous command)

su -c "fdisk -l"

.
Congratulations, you have successfully made a tri-boot live USB drive with room to spare for storage!

How-To: Make a Multiboot Live USB Stick

This is something that I wanted to do for a while to show those interested what Linux is like on the fly. However, I only finished this yesterday.
The USB stick in question is an 8 GB Sandisk Cruzer Micro.
The distributions used are PCLinuxOS 2009.2 (KDE), Fedora 11 (GNOME), Linux Mint 7 (Xfce), and the latest version of PartedMagic. These are the only distributions I've successfully put on a multiboot live USB stick, so I'll only talk about how to create this step.
In terms of setup before the actual live USB creation process, a few steps must be taken. As far as I know, due to Windows only recognizing FAT and NTFS partitions, the steps I used will only work on Linux. My preferred partition editor is GParted. Also, if you don't have UNetBootin, get it beforehand. Finally, make sure that your computer has a CD-RW drive and that you have spare empty CD-R/CD-RWs.
The first distribution to add is PCLinuxOS.
If there are any existing partitions, remove and replace them with a single FAT32 primary partition covering the entire disk.
Next, download the PCLinuxOS 2009.2 KDE ISO image from the Internet and burn the image to (not on) the CD-R/CD-RW. (If, after this step, the disk is ejected, reinsert it but close any autorun dialogs.)
Next restart the computer and (if necessary, reconfigure the BIOS to) boot from the live CD (that is, the CD with the PCLinuxOS image on it).
After that is all done, go to the PCLinuxOS main menu and click on "Make Live USB". Please make sure that the correct USB stick is being written to (you can check this as root in Terminal through the command "fdisk -l" and determining which USB stick with its free space correctly corresponds to your stick, if you know what I mean).
Restart the computer and, after modifying the BIOS to boot from the USB stick, make sure that the live USB works properly.
If it does, it is time to move on. (Revert the BIOS to boot from the hard disk drive.) If not, make sure that you followed all of the steps listed here in the given order.
To prepare for the remaining distributions, in GParted, trim the primary FAT32 partition with PCLinuxOS on it until there is about 100-150 MB of free space left on that partition. Fill the remaining unallocated space with an extended partition. Finally, fill this extended partition with 2 logical FAT32 partitions of size 850 MB (each), another logical FAT32 partition of size 400 MB, and a logical FAT32 partition that takes up the remainder of the extended partition.
The second, third, and fourth distributions are Fedora, Linux Mint, and PartedMagic. Download all of these respective ISO images from the Internet, and use UNetBootin and the "Disk Image" feature to write the images to the partitions. The Fedora and Linux Mint images should go separately in each of the 850 MB partitions, while the PartedMagic image should go in the 400 MB partition. UNetBootin recognizes partitions by disk drive name and number rather than by size, so to verify which partition is which, as root in Terminal type in "fdisk -l" to know which partition to write to in UNetBootin. After each write, verify that the live USB image works properly by booting from the USB. Each time a new image is written by UNetBootin to a partition, that partition is automatically flagged as bootable.
These steps will not allow you to select from all of the distributions which one to boot from (i.e. from a giant GRUB menu list upon booting). You much change which distribution to boot from manually in GParted by modifying the "boot" flag.
If you followed all of these steps and it all works, you should be good to go! If not, please leave a comment!