> I still haven't figured out how to swap to a file, or even a vnode -- I
> thought I had made all the right kernel changes to allow swap to a
> vnode, but it still won't allow me to attach it, and I just gave up.

Unfortunately, you have to configure and build a new kernel to do it.
Like this:

config netbsd  root on sd0a swap on sd0 and sd1 and sd2 and vnd0b dumps on sd0

I guess you are hosed...  The generic behavior these days allows you to
have a swap partition *only* on the same disk as the root fs, if I'm not
mistaken.  I have yet to hear a convincing rationale behind it.

ken