you actually dont need Unetbootin, usb-creator, etc
except in some circun=mstances
1) Plop bootmanager executable can boot usb, usb-cdroms, etc
on PC's that can or cannot boot usb as it bypasses bios.
Do you have Grub installed on your PC?
all the distro's run somewhat differently in "frugal" mode
frugal mode is basically the livecd compressed read-only media
as opposed to a hard drive install wherein the filesystem is decompressed.
Examples include Debian Live, Ubuntu, etc
all of them have different types of how they do persistence
With Debian Live for instance; the persistent file "live-rw" or labeled partition
must not be on the same partition your booting Debian Live from
In contrast is Ubuntu, which uses the "casper-rw" file or labeled partition;
the file can be on any fat32 partition including the one it boots from
while it cannot save to a casper-rw file on ext2/ext3
and ubuntu can boot fromiso too
Slax and its derivatives can save almost anywhere and to both files, and a persistent partition
Again, Puppy Linux saves to a file of whatever size, or to a partition
similar to Slax.
So, heres an example 8GB USB with fat32 as first partition
setup with Ubuntu, Debian Live, Fedora*, a Slax derivative**
Example USB is sdb
sdb1 fat32 boot flag "on", syslinux installed
Fedora+ persistent overlay
sdb2 ext3 (contains Debian "live-rw" file, Slax* "slaxsave.dat" file, Puppy "pup_save" file of whatever sizes...
*With Fedora I believe only Fedora's usb-creator can creat the persistent overlay
**Slax derivatives include
SlaxRemix07 (Slackware 13.1 based) http://www.slax.org/forum.php?action...parentID=62815
my own nFluxOS based on Slackware current
So, i will tell you how to get it all running but need to make sure
your interested as it can be a lengthy tutorial involving multiple OS'?