I see in 1.4 beta that in the options->Notifications->Advanced area, you can now run a script.
I have placed the following in the script enter box:
beep -f 800 -l 500 -d 500 -r 5
and hence when I have an incoming call, and I have forgotten to remove my headset from the audio
jacks of my laptop I still hear the laptop beeping away.
On Kubuntu, I had to install beep (sudo apt-get install beep)
Enjoy
