Above I have made a mockup of how I imagine a pulled out spell might look. You can use the same format as cooldown timers do with the text, appending "m" for minutes and a plain number indicating seconds, to save a little space. I would also abbreviate names but I do this already and am used to it. You would probably want to add some ability to select how the text was anchored to the button, particularly if you didn't limit the number of displayed cooldowns to some small number. Being able to make pulled-out buttons larger might also be useful.

I imagine this functionality would be most useful for a raid leader who needs to manage (or at least monitor) resources during a long, multi-phase boss fight. Most of my boss fights don't last long enough to warrant this.