Hello,
I think you can verify the first backup, however, this may slow down things 
a bit,  i have seen that option under networker user program, not sure how 
you would apply accross the board.
Also, tape drives themself do have  CRC and other check mechenism to ensure 
good backup, keeping clones onsite is a good suggestion, my whole problem 
with cloning is the time it takes to do it, by that time you would have 
lost your backup window.
Perhaps best way to achive this is with VLT such as ADIC Pathlight, where 
you can retain the backup data for number of days for onsight recovery and 
still meet your backup windows and send tapes offsite.

To sign off this list, send email to listserv AT listserv.temple DOT edu and 
type "signoff networker" in the
body of the email. Please write to networker-request AT listserv.temple DOT edu 
if you have any problems
wit this list. You can access the archives at 
http://listserv.temple.edu/archives/networker.html or
via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER