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!