Off of one of those I run a short cord squarish power bar then hook other power bars in, one per tank. That way if I need to immediately turn off ALL of one tank, click - its off.
The other method I use is to hook heater/light/filter of each tank into one of those orange 3-way connectors.
A fifty watt heater, 15 watt light and 12 watt filter don't add up to a single amp draw, so you could have fifteen small tanks all hooked up through one of these plugs.
Get yourself one of those ground-fault plug-blocks above, it WILL save a life - maybe yours, maybe your fish.