Brian,
Those are good ideas. I am guessing that most people's AC folder would be less than 200MBs. If it came to that, you could always just back up the .mdb databases. It comes in a 1, 2, and 4 GB version. The 4 GB is only $150 so I would think five copies coule be put on there. However, putting five copies on one key, offsite or not, would pretty much defeat the purpose of multiple backups.
Even with my obsession on protected databases, I think encrypting them at home would be a bit of overkill. With a different external backup such as USB hard drive or flash drive, TruCrypt would keep the file encrypted on both drives.
In the end, I am still a big fan of automatic backups at the site with easy manual backups to be sure and taking backups home weekly. I always look at the weekly backup as being the extreme measure.
At the very least, my recommendation would be two USB 2.0 external hard drives with folders numbers 1 through 10 with 1 on hd1 and 2 on hd2 and 3 on hd1, etc. Use Acronis or ntbackup or Backup Assist (very good and inexpensvie) to back up the entire computer at night. Use SyncToy to backup AC to both USBs. I say SyncToy, because it would take 20 seconds after the click rather than having to right click and copy and paste, etc. It's free. Try both methods. Then take a flash drive (encrypted) home on Friday.
If one were going to only use flash drives off site, then purchase five of the $79 1GB ones and bring Monday to work and Monday home. You will always have five backups.
These are just suggestions and may seem way too much for some. If some do one CD or flash drive, and they think that's all that is needed, OK.
Brian, I am pretty sure you can run it from the key and, in so doing, there are traces of the data on the PC. I am just a bit confused, because when we talked about syncing and I brought up the idea of moving the folder to the laptop, the issue was always if someone else used the PC while you were gone. So, with the flash drive at home, if you didn't come to the office on Monday until 10:00 AM and your staff was there at 8:00 AM, that may be a problem.
Ironically, my friend who used to use one CD backup a day and now has my ridiculously overdone backup system and who will probably start with AC in the first quarter of the year, watched the IronKey demo and bought the 4 GB flash drive right at my computer. So, we shall see I guess.