Edit: Unfortunately, the images originally included in this post are gone, because of hosting problems in late 2009. My apologies.
The technical answer is “no,” and the reasoning is that both Fluxbox (or Openbox, for that matter) and Beryl are window managers, and the two cannot co-exist, at least in the shape we would like.
That does not however, mean that you can’t run just Beryl, without Fluxbox (or Openbox, for that matter).
Install Beryl like you normally would, then change your
.xinitrc file to something like this.
Comment out any references to Fluxbox (or Openbox, for that matter). Start X from a terminal with
startx, and voila! Beryl running alone.
So what’s the catch? No menus. No panels. No right-click menus. No access to a terminal. You’re kind of stuck, trying to remember how to send a terminal command from a tty with the output to the X server and … urk!
You can circumvent that unfortunate empty and meaningless state by spawning a terminal window in the
.xinitrc file, like I did in the screenshot. And if you’re adept at the terminal, you can get anything done.
Or you could add something like fbpanel or lxpanel or perlpanel to your setup, do a little text editing, and you’ve got an exceptionally lightweight Beryl system running with just as many doo-dads as the Gnome crowd.
So yes, it is possible to run just Beryl alone atop X, and have a meaningful computing experience. It’s just not what you wanted: Beryl with Fluxbox (or Openbox, for that matter).