My SysAdmin friend came over after work and -- for the price of a dinner
when we were finished -- got my main workstation running again. Used a
slackware boot floppy, configured his notebook to be part of my network and
ftp'd the /bin directory back again.
When everything booted properly (kinda' trashed the / partition, but
nothing critical), we umounted /usr3. From the other machine (the one on
which /usr3 lives), there were all the root directories (/bin, /dev, /etc
and so on)! Now that /usr3 was isolated from the other machine, I could rm
-rf the spurious directories and not affect the other machine. Remounting
/usr3 put the system back the way it was originally.
Ver-r-r-r-r-y strange! But, it works.
First thing tomorrow, I swap the tape drives and make 2 complete backups.
Then I'll upgrade to RH6.0 and try installing the GRASS beta again.
I'm too old for this kind of excitement! 
Rich
Dr. Richard B. Shepard, President
Applied Ecosystem Services, Inc. (TM)
Making environmentally-responsible mining happen. (SM)
--------------------------------
2404 SW 22nd Street | Troutdale, OR 97060-1247 | U.S.A.
+ 1 503-667-4517 (voice) | + 1 503-667-8863 (fax) | rshepard@appl-ecosys.com