Description of problem: It would be nice to be able to reboot a reserved system from the CLI. In my particular case, I've got a long-running test that will (most-likely) repeatedly crash the system. The test is designed to automatically restart once the system is restarted. If I could reboot the system from the CLI, I can write a script to notice when the system stops responding to a ping, then reboot the system.
As of Beaker 0.6.0, we have an XML-RPC method (systems.power) and bkr client command (system-power) to control system power for reserved systems. See bug 644694.