The new feature "Hanging Build Detection Event" is a good starting point. But as far as I can see it can only notify someone to have a look at the build.

We use Bamboo to do lots of testing during weekends. There it normally does not help to inform someone as he will react after the weekend. This means that all builds that are sheduled after the hanging build will not run over the weekend. So it would be very helpfull if one could configure that a build deteced to hang could be stopped so that the next builds in the queue could start.