Stefan> Is there a place where I can download a boot.fs file from the current 
Stefan> tree? I only found 1.5.2 binaries so far.
Use one of them:
ftp> dir */binary/kernel/netbsd.GENERIC_M*
  2291017 Aug  3 05:33 20010801/binary/kernel/netbsd.GENERIC_MD.gz
  2407925 Nov 11 16:53 20011111-1.5Y/binary/kernel/netbsd.GENERIC_MD.gz

As far as you place these stuff on Macintosh HD, boot.fs and
netbsd.GENERIC_MD.gz do the same things. (There are so many things
different, but for your purpose..)
---
Makoto Fujiwara
http://www.ki.nu/software/NetBSD/iBook2/