A little hacking around gets us back (with current code!) to:
And unlike with the old PPC core it's actually trying to boot the ATAPI CD-ROM now. If I could find BeOS install disks we might get someplace.
All is not perfect though - for some reason it only boots if you run -debug. You can immediately dismiss the debugger and it'll boot, but that needs to be fixed. We're working on it (Oh, and the PPC change for this isn't getting commited to SVN quite yet - I want to try and fix the -debug thing first).