Quick and dirty redundancy, anyone?

I spent this weekend out in the archipelago with my girlfriend. I brought my camera, and ended up shooting quite a lot of pictures, it being a nice day and all. Pretty soon, my memory card was all filled up with 12MP JPG+RAW files.

Now, some people would call me a pack rat. I simply don't like throwing things away. Especially not pretty (or so I tell myself) pictures. So I thought to myself, where should I store these pictures? Quickly, as the techie I am, I came up with some different alternatives:

• Stash them on my servers
  
  This is perhaps the most natural alternative for a geek. "Just rsync the stuff to your server!" Yeah. This is a good idea, if it weren't for two things. 1) Servers require work and maintenance. 2) My current servers have like 40GB of disk space left. Replacing the drives takes time and money. Thus, goto 1.
  
  
• Keep them on the memory card and get a new one
  
  As stupid as this may sound, it's actually an appealing idea. Modern memory cards hold data for centuries, and the interface is very standard. Thus no irretrievable data later on. The practicality of just popping one card out and popping a new one in shouldn't be underestimated either. The downside is that it's ridiculously expensive to do this, in comparison to a hard drive based approach.
  
  
• Put them on my brand new USB drive (WD passport)
  
  Recently, I bought a USB hard drive. Kind of ashamed to say it's my first one. (What, I've used my RAID1-configured servers in the past, don't judge me.) This drive is a Western Digital Passport drive, and it's unbelievably cute. Come to think of it, I've actually been carrying it around my jacket breast pocket for half a week without even thinking about it. That's how small and light it is. And it runs off the USB power, so all you need is a USB cable.
  
  Anyway, an alternative would be to store the images on the external drive. However, having experience with IBM DeathStars and the like, I'm aware of the potential flakiness of mechanical drives. And this leads us to the topic at hand.
  

What if you could plug any number of USB drives into your computer, and then run a command that made sure that all files on all connected drives were stored redundantly. A post-write kind of redundancy, if you will. That way, you could write your data to the drives when ever you want to, and at a certain point plug them all into your laptop and add the redundancy. In a simple implementation, if a drive fails, you'd have to plug all drives into your computer to recover all data. I don't know if this would be useful, and I don't know if such a solution already exists. In either case, let me know what you think.