Hello Don.  My favorite way to do this, without using identical disks is to
perform the following steps.  We assume here that you have a working
machine running NetBSD which is of the same architecture as the machine you
want to install.

1.  Boot the fresh system with the install cd or floppies.

2.  Disklabel and newfs the hard disk on the system to taste.

3.  Ifconfig and otherwise setup networking so that you're 
able to exchange traffic with the working system.

4.  Make sure rsh from the new system to the working system works.  Use rsh
<working system> date to test.  You may have to edit /etc/hosts or
/etc/resolv.conf on the system you're trying to install in order to get
things working.

5.  Copy /sbin/restore from the working system to '
your temporary root drive.

6.  Mount your newly newfsed disk on /mnt.

7.  Create a symlink from /tmp to a new /tmp directory on your newly
mounted /mnt partition.

8.  Now run something like the following to do the transfer.

cd /mnt
rsh <working system> /sbin/dump f0 - /dev/rwd0a |</path/to/restore> rf -

If you have more than one filesystem on the working system that you
want to clone, make sure you dump each one in turn.  Before you dump, be
sure to cd to the directory on your new system where the filesystem was
mounted on the working machine.  For example, if you have /usr on the
working system, and it is a different filesystem from /, then cd /mnt/usr
on your new system before running the dump |restore pipe as shown above.

9.  Run /usr/mdec/installboot on your new system, or whatever you need to
do to make the disk bootable.

10.  Edit /etc/fstab and make sure the disk partitions and names are
correct.

Hope this helps.
-Brian