Hey gents! Thanks for the comments on the show. I guess I should have been clearer when I compared the synchronization features of Tmux to that of ClusterSSH. While I could have done the commands using ClusterSSH, I preferred leaving the multiplexing to Tmux on the FreeBSD box with the single SSH session from whichever client I was using to perform the duplication. The other reason I did it this way over using ClusterSSH is because I don't always need to SSH to the box since it's in my office, and doing it my way allows me to log in to the box directly from the console and then pull up the Tmux session to see the status of the duplication or even begin another session after swapping out the USB flash drives themselves.

As mentioned by Ken, scripting this is a possibility, but we all know not to treat dd lightly as that can be a recipe for disaster. I was thinking of hairylarry's technique of using abcde, but since that's only for ripping CDs, it won't work here. Of course, I'm open to potential episodes from others that know of a better way! ;-)