I got netbsd to successfully boot into single user mode from the cdrom
drive, all I did was grabbed the base.tgz and etc.tgz from the hpcsh
port,
ran MAKEDEV in /dev, ran
sh-elf-objcopy -O binary netbsd.elf netbsd.bin
sh-elf-scramble netbsd.bin 1ST_READ.BIN
rm netbsd.bin
made the cd as usual (make sure to add -rock to the mkisofs line)

If anyone is interested, I have a script for use in linux that finds
your
cdburner, extracts the tarballs with the propper ownership, makes the
nodes
in /dev with propper ownership, and appends a few lines to rc.conf, and
finally burns a self-boot netbsd cd.