yes ive done a market survey.
there are two approaches to this. one being the pump plus small tank mounted on top of it that you mentioned.
2nd method, one im more interested in....this kind of pump coupled with an electronic pressure switch. they are available in the market. They sense when water flow has started and switch on the pump, its almost instantaneous. The pumps can pump out at around 10bar max pressure.
The only thing im concerned about is what happens when electricity loadshedding occurs? Are you sure the water flow will be back to normal and not completely cut off?