It would be really useful to have a time limit on plans so that if it this time is exceeded, the build is forcibly stopped (by actually terminating the process) and the plan is marked as failed.

We occasionally have builds which just get stuck while doing unit testing (due to, say an error in a unit test). Unfortunately, this will block all other plans on the server until someone manually kills it (and even then the only way I've been able to do this with bamboo is by killing the actual process).