If you get a chance to try a Hybrid version of a PCLOS ISO on a USB stick or partition, I would be interested to hear the result.
I would expect it to fail in the same manner as the LiveCD based on your test so far.
Unfortunately I have only one USB stick, and it's currently filled with data I need to transfer to someone else's machine, so that could take a while.
You'll like this next bit.
Created an isohybrid version of pinoc's latest MiniMe and used dd to write the image to the USB stick. On reboot, it did not fail with the expected error message, but rather offered the normal boot menu options. Selecting the no splash 2nd menu item, all goes as normal until it reaches the searching for loop image stage. First it checks /dev/sr0, then /dev/sda1 through /dev/sda11, and /dev/sdb1 through /dev/sdb5, then gives a final [OK] and drops to a limited shell after announcing it could not find the image.
The problem with this is that there are 17 partitions on /dev/sdb, followed by 9 partitions on /dev/sdc, and finally by /dev/sdd on which the hybrid image is actually burned. The image search ended prematurely, and did so at exactly the same place on five successive attempts.
I next burned the hybrid image to disk, thinking the hybrid additions would allow the normal boot menu to appear, but on reboot got the old familiar;ISOLINUX 3.85 2010-02-20 ETCD Copyright (C) 1994-2010 H. Peter Anvin et al
No DEFAULT or UI configuration directive found.
Went back into BIOS and set the USB HDD as first boot device, and the optical drive as the second boot device, left the burned disk in the tray and reinserted the USB stick drive. The end result is that the USB stick image brings up the boot menu, all goes as normal until searching for the loop image, which it now finds on /dev/sr0, (the burned disk, and first item searched) and a normal boot to a live session is achieved.