The informations present in the previous versions of the howto (<=1.34), and reported in the current document, which apply to releases up to and including 6.1 of Redhat Linux, is believed to apply to distributions that are Redhat clones such as Mandrake. The procedure is reported to be untested (as you can read in the howto itself) though.
Similar considerations apply to the LinuxPPC distribution for Apple PowerMacs. When making a distribution for the PowerMac platform, you need to use mkhybrid) instead of mkisofs and this should be the only difference.
The informations supplied for the new releases of Redhat (>6.1) shouldn't work with Mandrake, which has now a fairly different installer from the Redhat one. I really don't know if some other clone of Redhat can have its distribution CDs updated this way, but I would be happy if you let me know.