>I can boot from the net, drop into a shell, mount /dev/wd0a, and see that
>everything is where it should be, so I don't imagine this is a hardware issue.

Boot from the net.
ln -s /netbsd /boot
reboot

And see if that helps.

-- 
Phil Nelson                    NetBSD: http://www.netbsd.org
e-mail: phil@cs.wwu.edu        Coda: http://www.coda.cs.cmu.edu
http://www.cs.wwu.edu/~phil