I have been wanting to do this for a while, so this morning I have been playing around with it. I have not been able to successfully complete a boot, but I have got to the point where it fails to load the livecd. See below:
What I did was to extract the contents of an iso file, I guess that any PCLOS release will do. Then I copied the contents over into a folder, my folder is "PCLOS", on the pxe server. The boot code in the .cfg file is as follows, but you may change yours to suit your needs and configuration:
append initrd=/PCLOS/isolinux/initrd.gz vga=791 fetch=http://192.168.1.4/PCLOS/livecd.sqfs
I "hope" that I just don't have the correct code on the third line above. I am at a dead-end on this, for now, until I google and try some cheat code stuff. If you or somebody else can get the livecd to load then I will be grateful.