A company called ENTECH http://www.entechsolar.com/ (go to the "technology section to see a module cross section)
seems to be producing solar-electric products that use the Fresnel lens as a concentrator. One product already installed is a 25-kilowatt "SolarRows," (single axis tilt) .... also a stand-alone power unit on two axes, producing 1kw at peak output.
http://www.mdatechnology.net/techsearch.asp?articleid=226
