How does one make a bootable i386 CDROM with an FFS filesystem on it? 
(Assuming this is possible.)

My wild guess is that the disk image would need a small ISO filesystem
at the front to contain the "El Torito" boot information, which would
just contain a traditional BSD boot sector; then the BSD disklabel (in
the unused portion in front of the ISO filesystem) would describe a
BSD 'a' partition which starts just after the ISO filesystem.  Is this
right?