> Any particular reason why 32-bit mode is required?

Memory in the MacOS is in a more "sane" state when the machine is in
32-bit mode.  If you'd like to look into supporting a 24-bit mode boot,
feel free...  I'll even merge your changes in...  ;-)

For some details on the different memory layout, try booting with and
without 32-bit mode and look at the different layouts for "system RAM"
and "NuBus space".

Seriously.  If there's anything you (collective "you", not anyone
specific ;-) don't like something about NetBSD or anything you think
could or should be done better, do something constructive about it.
My needs are not necessarily yours, and I tend to work toward my
needs (and whims).  Again, this is not directed at anyone in
particular...  ;-)  [ And yes, I know it's hard to do anything when
NetBSD doesn't work on your machine yet... ]

-allen

-- 
Allen Briggs - end killing - allen.briggs@bev.net ** MacBSD == NetBSD/mac68k **
   Where does all my time go?  <a href="http://www.netbsd.org/">Guess.</a>