Greetings
Having read this:
http://xmodulo.com/boot-iso-image-from-grub.html
I wondered what the grub config (/etc/grub.d/40_custom) would be for the KDE5 test iso?
If you are click averse, the subject is finding that config similar to this Fedora example:
menuentry "Fedora 20 Live Desktop x86_64" {
set isofile="/boot/Fedora-Live-Desktop-x86_64-20-1.iso"
loopback loop (hd0,1)$isofile
loopback loop $isofile
linux (loop)/isolinux/vmlinuz0 root=live:CDLABEL=Fedora-Live-Desktop-x86_64-20
initrd (loop)/isolinux/initrd0.img
}
This is a great way of running an iso that I've only just started using.