I was thinking there was a specific thread where someone was summarizing viable external solutions, but didn't find it. Not sure if this is a good place for that, or not? But....
I have these two items in combination, and would like to report that they seem to work flawlessly. I'm not much for this idea that some folks have pushed that you don't want to leave USB hard drives on for extended periods. Certainly, that makes sense if you have them in some semi-cheap enclosure that simply does passive cooling, but I run a complex computer setup with a lot of hard drives (some in external arrays and some not), and I have that stuff running all of the time, so I'm in the habit of expecting to have things "ready" when I want to use them. I also don't want to be worried about having left my DVR-based USB drive on "accidentally", and be wondering whether it's going to get fried due to overheating.
So... I nabbed this enclosure (part # N0012US R), which has a whisper-silent fan (certainly the 622 is far louder than this fan), and also grabbed a Hitachi 1GB drive (their part # 0A35772). Put it all together in about five minutes, and the 622 recognized it just fine. Formatted out to about 930GB of available space. Copied stuff over, plays just like it did on the local drive. Trick play seems to work flawlessly. Bottom line, I'd certainly recommend this solution, especially if you don't want to be worried about heat and/or hassling with turning something off and on all of the time.
All, FWIW.