The wind turbines above, from 5 kW to 10 kW, are small turbines. A smaller 1 kW wind turbine, weight 60 kg: Aeolos Wind Turbine Company – 1000w Wind Turbines – Horizontal Axis Wind Turbine - 1kw Wind Power Generator.
Still smaller, these are toys as you say. Kitewinder needed a 4 m² kite for an about 1 m² (swept area) and 0.5 kg wind turbine of 200 W. A classical 200 W wind turbine sweeping also about 1 m² weighs more than 6 kg. We see what the mass of the generator represents, leading to the considerable difference between 0.5 kg (generator on the ground) and over 6 kg (generator included).
Do the calculation. Even for a classical wind turbine of only 1 kW (60 kg), a very large kite is necessary.
Kiwee (with its rope-drive transmission) is lighter, so it is an option. How far can it scale?