I wrote something similar in the past. It's tailored for my need but the idea behind it is very similar. It brings up window with hotkey allows to write simple command and params and run it.
Oh cool, you even went for Python 3 + PyQt5 and a module idea. Interesting! Seeing how your post was from January 2016, we may have started our projects around a similar time, even though mine started as a simple front-end for https://www.passwordstore.org/, back in December 2015, starting to support other functionality in, interestingly enough, also January 2016.
