So that means batteries, or pulling power from the source device
I'm in a similar situation and my plan is thus:
1. Buy two mid-range external hard drives, and store one at home, and one at work/somewhere a few miles from home
2. Store the "live" copy of the media on a single source (laptop/server/NAS/whatever)
3. Every weekend, backup the media from the source to the drive stored at home
4. On the first weekend of each month swap the location of the two external drives
This way you have three copies of the data, one live, one at most a week old, and one at most a month old. If the worst happens, you lose only one month of media. When one of the drives inevitably fails, replace it and do a backup/restore depending on which drive failed.
For extra protection, mirror the "live" source using RAID or similar, and buy a fire-proof safe to store the home-backup in
It's essentially the same thing as when you want to run two webservers on port 80, it simply doesn't work.
Uhhhh...yeah it does. Host headers.
Uhhhh...no it doesn't. That would be one webserver running two web sites.
Center meeting at 4pm in 2C-543.