Yes, the LinuxPPC 2000 CDs are burned using Toast, which has the drivers for making it bootable on an oldworld box. If you look at the partition map on the CD (yes, Mac CDs are partitioned) you'll find something like this (this is the LinuxPPC 2000 MacWorld edition):
<snip>Ok, that's what I was afraid of. (Why didn't I think of looking at the partition map? Darn it. :) And now that you mention it, I suppose in this case "no proprietary software" rules out use of Apple's drivers altogether?
NRH