> This could involve a lot of work. Rather beyond me at this stage. I > notice that Progeny uses Grub, but as far as I can see it does not have CD > support.
What do you mean exactly by CD support in GRUB? You want GRUB to be able to read an ISO-9660 filesystem from a CD? The way booting from ISO-9660 CDs works is that a file on the CD contains a floppy disk image and the BIOS acts like that image file is the floppy disk drive. I think GRUB uses the BIOS floppy calls, so it will just be fooled as intended.
