First board iteration is available on Tindie: USB micro wedge
Second board iteration is also available on Tindie: USB power micro wedge (5V programmable)
Limited quantities! While supplies last!
This is a simple project to interrupt the power of a USB cable
If I understand the use-case correctly, how I solved that problem is to use cables with magnetic ends on them. That way I can say connect my cell pone to the charger once or twice a day without having to unplug the connector (just disconnect the magnetic connection).