No, unfortunately I don't know about those Stuart, looks interesting though since I recently unearthed a trove of cassettes. I just wanted to interact with the other helical thread within this thread about off-computer storage.
USB drives I don't trust all that much, in fact
not at all, since I've had two reputable brands go south on me.
A better solution for taking big media folders and scheduled backups off the main drive might be a NAS, network area storage, if you're prepared to budget a little higher. These have now come down in price into the consumer zone, they were once only in the domain of corporate data centers.
This is basically a 'not entirely dumb' racky-type dedicated storage box into which you can plug multiple SATA hard drives, which you can get at any big box retailer, of the size, speed and $$ of your choice. I recommend keeping the drives smallish (relatively speaking), 1 terabyte would be the max size I'd chose for a single drive at this point in time for various tedious geeky digital- and mechanical reasons but if you have a four-slot NAS that's huge.
So anyway, you plug in the drives and connect the NAS to your computer via your network and it's basically just another computer on your network dedicated to storage. To connect it to more than just your computer you will need need a gigabit switching hub ($50 for a 5-port Dlink, is a good one), and don't skimp on the cables, CAT 5e or CAT 6, and the shorter the better for power reasons. You plug your computer's network cable into one port on the switching hub, and the NAS into another, and your internet connection into another. Plug any other computers, TiVos, Blu-Ray players, TVs, anything with a network connection, into the remaining ports on the switching hub or other connected hubs on your network.
You then run the supplied config software on your computer and at the end of the day the NAS drives come up as one or more mapped drives on your computer, and are available to any other device on your network, should you have them, and have elected to share the NAS during the config stage.
Advantages are speed, huge expandability (if you get a four drive-space NAS), and connectivity to everything on your network. There are further less tangible benefits to do with the box's infrastructure like thermal control (they have built-in fan cooling), greenness (look for one that will sleep when nothing is accessing it, saving the planet and saving you money) and thereby extended TTTF (total time to failure).
Hope this is helpful.
[update, 4 months later: I ended up getting a 5 drive space NAS with 5 x 2 Terrabyte WD drives, formatted into a RAID array. Raid type I elected to go with is SHR which gives 1 disk redundancy and 7.14 Tb available storage. Google Synology NAS DS1511+ for details. It's been flawless so far, and the management software is excellent, highly recommended]
