Just in case anybody is still looking for a z50, I found a store still
selling brand-new z50s for a decent price.

http://www.apcforless.com/mall/IBMZ50.asp

Note: I am not affliated in any way with the above website, I just found the
link myself moments ago.

I've bought two of these (not from this source) already. One for me and one
for a buddy. Another friend saw my unit and wants one, too.  These are great
units.

Robert Taylor