You're referring to a limited self-contained application (such as residential house-top solar panels), correct? In that context, wind/solar makes sense.
I'd be more interested to learn if there are any commercial power wind/solar installations that can operate profitably without subsidy - I'm extremely skeptical that any of those could operate profitably without government propping them up. The only place in the US where it might make some sense is Hawaii, considering the steady trade winds and high cost of importing conventional fuels.
I found this...does it help?
Preliminary results indicate that about 26 TWh of wind-generated electricity can be profitably developed per annum by the year 2010 and 34 TWh per annum by the year 2030 in the 36 specific sites.
http://proceedings.esri.com/library/userconf/proc99/proceed/papers/pap781/p781.htm