I have been using https://extensions.gnome.org/extension/437/mylauncher/ to execute shell commands, to see output I have just found this: https://extensions.gnome.org/extension/912/command-output/, but I haven't tried it yet.

I wrote one for the Cinnamon Desktop a while ago:

https://github.com/abgoyal/ShellToolsApplet http://cinnamon-spices.linuxmint.com/applets/view/136

Conky is great for this sort of thing.

I haven't used conky in a while, but can you interact with it now?

I was checking the plugins and some of them allow clicking on items in the dropdown and having an action execute.

The clipboard history now has code for this.