'Twas brillig, and Lukasz Stelmach at 03/08/09 18:29 did gyre and gimble:
I knew I've forgotten something. XOSD!
Hehe, not quite!
I don't use any of the bloated desktop environments and I couldn't find a tool that does the job. Can you name one and I promise I won't trouble any one here with my ideas. If you don't... I won't be bothering you too much either ;-)
Well I'd have a play with Gnome (whose current interface is much nicer than the KDE one), which pops up a nice translucent display whenever I press the buttons on my lappy's volume control panel.
Not sure which process actually does this UI, but I'm sure it wouldn't take long to see it.
Just google for various screenshots (including some Ubuntu patches to add it to notification daemon instead of standalone).
Col