Is it possible to either power on and off lightweight PoE-connected APs from the central controller and/or explicitly tell the AP to go from high-power mode into low-power mode (with all radios turned off) and vice versa?
(Ideally I'd like to do this via CLI or some other kind of scripting).
You can use an AP template from WCS to turn on and off the radios as well as adjust the power settings. These are under the 802.11a/n and 802.11b/g/n tabs of the AP template. These can also be scheduled.