It would be really ace to be able to inhibit breaks when certain external displays (or types of external displays) are connected. The use case is when I'm teaching a class; I'll connect my macbook to a projector, and don't want the break to appear. Having said that, I use an external monitor for normal work, so I still want breaks to appear when connected to that one. It should be possible to query the ID of the connected display to work this out.
For bonus points: prevent the computer from going to sleep when certain types of displays are connected. I'd pay money for an app that does just this.