These are steam thermoelectrics. They could also use heat engines. If they did that, they could heat a very large quantity of water, which would remain hot into the night, and still pass it across the heat engines. In fact, because the night air is cooler, they could get more power from the hot water at night than during the day, as long as it is well insulated.
The most efficient system ever built for utilizing solar energy was not a PV panel, but a small kinematic stirling engine that worked off sunlight reflected from a parabolic mirror array. It looked like a large solar dish. Several such units have been built. One company is here:
http://www.stirlingenergy.com/Preliminary research into stirling engines using thermoacoustics has shown that they can acheive the same efficiencies as the kinematic stirling engines, with fewer moving parts. (In fact some may be possible where the only "moving" part is quasi-solid-state.)
Thermoacoustic stirlings can also be made into heat pumps that do not bother to change the energy into electricity and directly produce cold air when you heat the collection end.
However, most of these green energy companies tend to get wrapped up in making ever-more-efficient products rather than cheaper products. They are well past the point of diminsihing returns, at least until the industry picks up a large economy of scale. If they concentrated on making cheaper solutions, and just using more real-estate, they could probably break the wind-energy price point.
All that said, I'm a bit more interested in seeing power generation right on the premises, owned by the homeowner or apartment complex owner, rather than by energy companies. One good start would be a mass-produced product like an window-mount solar air conditioner, priced cheap, that would work during the day in conjunction with the normal air conditioner to reduce load. Such a product would have no need to store power for later use, and would take a chunk out of peak demand on the grid during the summer.
Unfortunately most green energy R&D folks follow the money, and the people that have the money are energy companies and venture capitalists, not the homeowners/landlords. So most research gets poured into creating these large installations, when in fact, the technology they use doesn't get much more efficient when you scale it up (wind does, stirling engines and mirrors do not.)