Flash Drives: Archival Media?

I have lots of client data to backup. I use tapes for long term storage of data I'm hopefully never going to have to pull off, but if I need to, I can. Our total amount of storage is such that a full backup now takes over 2 days to store, on 3 320GB tapes. It's a lot of data.

There are times, however, when I just want to archive a small bit. For example, I have a 5GB (compressed) chunk of data I'd like to archive and send to the ClientManager. I could send it over the network, but there's a T1 between me and her. That would take a "long time", and it would take up unnecessary space on her computer. I could store it on the fileserver, but that's the space I'm trying to free up.

If it were just a little bit smaller, I'd send her an archival DVD of the data, but 5GB won't fit, and it won't compress any further. There are some very high density optical disks on the horizon, but without spending thousands of dollars, I don't see a solution down that path.

So here's what I'm considering. Write the data to tape, as normal, but in addition, provide the client services manager with the data encrypted on a flash drive. I can use full disk encryption with TrueCrypt, which will work on Linux, Mac, and Windows, and provides for the security of the data. In addition, if the drive breaks or gets lost, we've still got the original tape archive in storage.

Any thoughts?