Any suggestions on how to solve this issue?

For the visual bell, somebody should file a bug against compiz, and whatever other window manager people would be using.

For the audio bell, I have no idea. We only set whether audio bell should be used, and GTK+ acts up on it. Lennart?

Normally I would suggest doing bell handling in g-settings-d. However I fear that this would be very unpractical.

The main reason why metacity handles the bell seems to be the visual bell and that only a single process can hook into XKB to handle the bell. It makes a lot of sense to implement the visual bell in the wm, since this requires drawing on the screen. And hence the audible bell needs to be handled in the wm too.

I don't really see this as much of a problem, since triggering the actual bell sound with libcanberra in the wm is trivial and just a matter of a single call. 

Hence I would suggest patching both compiz and metacity to include calls to libcanberra for the bell. 

*** Bug 525633 has been marked as a duplicate of this bug. ***

Does the 'doesn't cooperate with pulseaudio' problem explain why visual bell appears to have been disabled in F10 (for me), or is that another bug#/problem? (I'm still running metacity but am now running PA.)

(Never mind on the last question; turns out that is a side-effect of the new sound preferences work.)

Filed bug 630887 and bug 630886 against metacity and mutter.