The economics of solar for this use look pretty good for some areas of Australia.
If you take Nanosolar's idea of building Municipal power:
http://nextbigfuture.com/2008/04/solar-thermal-municipal-power.html

Then you have a reasonable 2-10MW power system, which can be built on the ground and so would have easy maintenance and erection, and which would not need transmission to distances or even stepping down.
If we then throw away some of the first advantages, and build the solar arrays as a roof structure then you have garaging shaded from the sun.

First solar quoted a cost of $1.29/watt some time ago, so by the time you have put it in a system you might come out to $3/watt or so.
EV's do around 3miles/kwh, so if you allow 20 miles as the average two-way commute you might need 6kwh or so.
At 30degrees from the equator this is the pattern of solar incidence over the year:
http://www.powerfromthesun.net/chapter1/Chapter1.htm

See figure 1.6
So at that latitude just eye-balling it you might get around 40% of the rated capacity over the course of the day at the spring and autumn solstice.

If you rated the system at 1.5kw per car that would give the needed 6kwh at those times of the year, with a shortfall in the winter balanced by a surplus in the summer when it is most valuable and of course a power supply to the grid over the weekends when the office would perhaps be closed.

Putting the numbers together that is around $4500 per car, over 7 years or so that is about $650 per year, or $3.5 per working day (200days)

A lot of people would pay that to park their car in a shady spot anyway! - and the fuel is then 'free'