Thanks to Parag Patel's information and a bit of superstition I seem 
to have gotten things working.

What I did was delete everything from nvramrc.  Then I put in two 
lines from system disk which may or may not be needed, harmful, or 
who knows.  I don't know forth.  The lines are:
hex
: $E device-end ;
Then I put in both of the patches on our web page:  the video 
settling time one and the wBoot delay one.

I have load-base set to 6C0000, boot-command to wBoot, boot-device to 
scsi-int/sd@0:0, boot-file to netbsd, use-nvramrc? to true, 
auto-boot? to true.

I've power cycled the machine a couple of times and it comes up into 
NetBSD properly.  The screen still looks like hell around the edges, 
but the screen patch never did seem to fix that all the way for me, 
and I want this as a server anyway.

Now I suppose I have to ruin all this stuff in order to get back into 
MacOS so I can set the reboot after power failure bit in the power 
controller.  <*sigh*>

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