@grouter, the house is pretty old and so the outlets in the bedroom are single-receptacle, ungrounded. Testing what the mystery switches do is as simple as plugging an illuminated lamp (i.e. one where the bulb is switched on) into each outlet and seeing whether the switch causes it to toggle.
Even though I have antiquated wiring I do have Peanut plugs in the living room doing their job well (in tandem with an Almond+), but in that case the lamps turn on/off on a timer, whereas I want "on-demand" in the bedroom. That's why I'm looking for a wall switch that works with my A+.
Note: In case you were wondering how I'm using Peanut plugs in an ungrounded system, the relevant living room outlets have been upgraded to GFCI-type outlets, clearly marked as "NO EQUIPMENT GROUND", which is an exception allowed by National Electrical Code to replace two wire ungrounded outlets.