Well, I stripped my A3000UX down and moved it so I can get at it. I copied the OS4 install CD onto a hard drive partition and unplugged the CD to make absolutely sure I don't have termination issues.
I got more patient and let it brew for half an hour and finally it's doing something that looks like OS4! And, my PPC chip is actually getting REALLY hot. Good thing I've got a 24" fan on it!
Learned something already! Disable DF1, DF2, and DF3 by jumper if you're not using them, or the install will hang for about 5 minutes per disconnected drive and doesn't tell you until it eventually gives you an error req.