For one thing, I think you seriously need to look at backup up to offline hard drives, instead of tapes. Unless you really want/need to archive the tapes for seven years
Well, the scientists are talking longer than 7 years so HDs just are not going to cut it
We back up to backup servers, then, every couple of weeks, I run rsync backups (well, we have a locally-rolled system to run the rsync) onto offline drives - in our case, I swap large drives into an eSATA drive bay. When I'm done, they go in the fire safe.
That's what I'd prefer to do :-)