The hybrid approach you describe would require twice the surface area and probably wouldn't double the output.
I think I prefer the idea of having large plants like these, with 'night'-time capabilities and a relatively steady output. That sounds like it would work pretty well in combination with decentralized roof top solar + smallish home batteries.
Of course, there's nothing wrong with the photovoltaic part being distributed in the form of rooftop solar, which is what's already increaslingly happening. Home storage batteries for load leveling are picking up nicely too, which is good because they're going to become mandatory within the next decade if we want metropolitan power grids to survive tens of megawatts of sometimes-rapidly-fluctuating solar power being dumped into them.
And we didn't even start playing with Sodium as a replacement for Lithium in those batteries.
Batteries have two things going for improvements in the batteries themselves and more energy efficient homes and appliances. PC won't replace utilities in densely inhabited regions, but batteries may help evening out variable sources.
Hybrid just means that it uses both approaches. I'm suggesting a solar thermal plant which is generally lightly loaded or unloaded during the day, storing the heat in a large reservoir while a neighboring PV plant much more cheaply covers demand. Then when the PV plant can't generate due to cloud cover or night time, the thermal plant steps up and uses the stored heat to generate power.
It's no different in principle to a hybrid car where a battery electric drive system cheaply covers as much driving as it can, and an internal combustion engine kicks in when required.
This article [3] analyzes some of the merits of this approach.
[1] (Partial paywall) http://social.csptoday.com/technology/integration-csp-and-pv...
[2] https://en.wikipedia.org/wiki/Copiap%C3%B3_Solar_Project
[3] http://spie.org/newsroom/6018-photovoltaics-and-concentratin...