I'm coming to this discussion late as I've just joined this list (so I
can't reply to the original post as I'd like to), but on Debian I was
able to create a bootable Fedora live CD/installer on a USB stick as
follows:
1) Write MBR to stick
Debian has a program to write an MBR. On Fedora you can do:
# cat /usr/share/syslinux/mbr.bin > /dev/sdb
2) Cat iso to disk, i.e.
# cat fedora-img.iso > /dev/sdb
Like the OP, I first tried dd to copy the image which didn't work but
cat does. I'd be interested in why that is.