Yup...buy a Duracell 9V battery and take it apart. Voila! 6 AAAA batteries. Be adivised though, they're "nubbed" on the negative end not the positive end. Also, you might have to make a little spacer because they are just a tiny itty bit shorter than "normal" AAAAs as I understand it.
When I took apart the Duracell battery I had laying around the 6 AAAA batteries were shrinkwrapped togerher and then individually shrinkwrapped, unlike CR223s where (aparently) the 2 internal cells are bare metal on the outside.