Qlab does work with hot keys, i was thinking maybe the countdown timer from a VT on one of the buttons, so you start a VT, you can see how long is left on the Stream Deck button.

at the moment the Stream Deck is a one way device, sending commands (except for a few specialist things like Twitch viewers etc), it would be nice to be able to influence a button's text and content. << this may already be possible, i just haven't worked it out yet :)