I'm sorry that I don't have an actual app to request, just an idea for one. I tend to change the volume on my computer a lot and hate having to click on the icon to bring up the slider.
I was thinking it would be a good idea to have an app that sets hotkeys to change the Master Volume on the computer. Something like Ctrl+Shift+Up to increase the volume and Ctrl+Shift+Down to decrease the volume and maybe Ctrl+Shift+0 to mute. I know this could conflict with other hotkeys, but it is just an idea.
If anybody feels like creating a program for this or if anybody knows of a portable program that already does this, please let me know.