"Keyboard Shortcuts" config applet doesn't allow user shortcuts (among other things)

Binary package hint: gnome-control-center

I'm not sure what the package is, the program is "gnome-keybinding-properties". This would be a very nice program, if it would be a bit more configurable.

The most annoying thing is that it's impossible to add new operations. For instance, I would like to have a shortcut to rotate the orientation of my screen. That's an easy command, "xrandr -o left" -- why can't I add it there and use a shortcut for it?

Second, I'd like to be able to enter several shortcuts (at least two) for some commands? Sometimes I like to have shortcuts in two different places, one for when I'm typing (so my hands are all over the keyboard) and one for when I'm doing something else and I just want to press a key combination one-handedly.

Third, I'd like to be allowed to see (and change) what the built-in commands do (at least when it's accessible from a different command). This would allow me to learn and tweak the commands.

Fourth, the applet is really fussy about Start-button shortcuts. For instance, right now I can't get the computer to lock the screen using start+L, though Ctrl+Alt works. (Start is reliably detected as Mod4, so it's reasonably-well configured.)

Fifth, I'd like it to integrate commands from other applications I have installed that use global shortcuts. (For instance, I use Amarok with several global shortcuts. Why should I go somewhere different to configure them?)