What other issues besides the apparently overcomeable XCOFF limitation are
there for powermac usage which are still pending?

As an aside, someone mentioned being able to boot from an application
directly into the OS...well, with a trivial modification to Boot Variables,
you can do that in linuxppc as well.  It still has to cause a reboot,
because Open Firmware is unmapped after boot; NetBSD needs to get device
control through the Open Firmware, which means it needs to see a mapped OF,
which means booting.