Is it possible to shrink the volume on my filer by a disk and have the free'd up disk be my spare?
You'll hear this from everyone: You can't shrink a volume except by destroying and re-creating it.
Does anyone on the list have a ST39173WC they would be willing to sell to me with our without the enclosure? (I have two broken ST39173WC's so I could re-use my enclosure.)
You'll need a disk with NetApp's custom firmware, most likely. The prices here look reasonable: http://store.berkcom.com/allnetappdisks.html
Regards,
Marion