That's the one! "rockbox_default".
I loaded up the cabbie that comes with the Fuze and it's not the same. It's nice, I'm using it now, but the Commodore 64 look of "rockbox_default" was really cool. Like you said, it was like not having a theme.
I'm not complaining. Rockbox on the Fuze is excellent. I just miss that bare bones look.