Just a quick partial reply:

Roland Dowdeswell wrote:
> I'm not sure which changes you are talking about, it has always
> been possible to set up root without a password hasn't it?
> 
Not last time I installed NetBSD (circa 1997).  (I don't remember 
what version.  I have the i386-install from that era on my hard drive 
even today, but it only says "Congratulations, you have successfully 
installed NetBSD _VER.")

According to one thing or another that I read, there was a change to 
sysinst in 1.5.  Since I wasn't paying attention at the time, I don't 
know when 1.5 came into existence. 
-- 
William Allen Simpson
    Key fingerprint =  17 40 5E 67 15 6F 31 26  DD 0D B9 9B 6A 15 2C 32